Podcast
Questions and Answers
If $\triangle ABC \sim \triangle DEF$ and $\frac{AB}{DE} = \frac{2}{3}$, what is the ratio of $\frac{BC}{EF}$?
If $\triangle ABC \sim \triangle DEF$ and $\frac{AB}{DE} = \frac{2}{3}$, what is the ratio of $\frac{BC}{EF}$?
- $\frac{3}{2}$
- $\frac{2}{3}$ (correct)
- $\frac{9}{4}$
- $\frac{4}{9}$
Which of the following statements is true regarding similar triangles?
Which of the following statements is true regarding similar triangles?
- The areas of the triangles are equal.
- Corresponding angles are proportional.
- Corresponding sides are proportional, and corresponding angles are equal. (correct)
- Corresponding sides are equal in length.
In a right-angled triangle, what is the ratio that defines the sine of an angle $\theta$?
In a right-angled triangle, what is the ratio that defines the sine of an angle $\theta$?
- $\frac{\text{adjacent}}{\text{hypotenuse}}$
- $\frac{\text{opposite}}{\text{adjacent}}$
- $\frac{\text{adjacent}}{\text{opposite}}$
- $\frac{\text{opposite}}{\text{hypotenuse}}$ (correct)
Which trigonometric ratio is the reciprocal of $\sin \theta$?
Which trigonometric ratio is the reciprocal of $\sin \theta$?
What is the value of $\cos 60^\circ$?
What is the value of $\cos 60^\circ$?
In a right triangle, if the opposite side to an angle $\theta$ is 5 and the hypotenuse is 13, what is $\sin \theta$?
In a right triangle, if the opposite side to an angle $\theta$ is 5 and the hypotenuse is 13, what is $\sin \theta$?
If $\tan \theta = 1$ and $0^\circ < \theta < 90^\circ$, what is the measure of angle $\theta$?
If $\tan \theta = 1$ and $0^\circ < \theta < 90^\circ$, what is the measure of angle $\theta$?
What is the value of $\sin 30^\circ + \cos 60^\circ$?
What is the value of $\sin 30^\circ + \cos 60^\circ$?
In the Cartesian plane, an angle $\theta$ has its terminal arm in Quadrant II. Which trigonometric ratio is positive in this quadrant?
In the Cartesian plane, an angle $\theta$ has its terminal arm in Quadrant II. Which trigonometric ratio is positive in this quadrant?
An observer looks up at a bird at an angle of elevation of $30^\circ$. If the bird is 10 meters above the observer's horizontal line of sight, what is the horizontal distance between the observer and the bird?
An observer looks up at a bird at an angle of elevation of $30^\circ$. If the bird is 10 meters above the observer's horizontal line of sight, what is the horizontal distance between the observer and the bird?
If $\cos \theta = \frac{1}{3}$, find the value of $\sin^2 \theta + \cos^2 \theta$.
If $\cos \theta = \frac{1}{3}$, find the value of $\sin^2 \theta + \cos^2 \theta$.
Given $\triangle ABC$ is a right-angled triangle with $\angle C = 90^\circ$, $AB = 10$, and $BC = 5$, find the value of $\tan A$.
Given $\triangle ABC$ is a right-angled triangle with $\angle C = 90^\circ$, $AB = 10$, and $BC = 5$, find the value of $\tan A$.
If $\sin \theta = \frac{3}{5}$ and $\theta$ is in the second quadrant, what is the value of $\cos \theta$?
If $\sin \theta = \frac{3}{5}$ and $\theta$ is in the second quadrant, what is the value of $\cos \theta$?
A ladder leans against a wall, making an angle of $60^\circ$ with the ground. The foot of the ladder is 2 meters away from the wall. How far up the wall does the ladder reach?
A ladder leans against a wall, making an angle of $60^\circ$ with the ground. The foot of the ladder is 2 meters away from the wall. How far up the wall does the ladder reach?
What is the exact value of$\sin(22.5^\circ)$?
What is the exact value of$\sin(22.5^\circ)$?
Two similar triangles, $\triangle ABC$ and $\triangle DEF$, have areas of $16 \text{ cm}^2$ and $25 \text{ cm}^2$ respectively. If $AB = 4 \text{ cm}$, what is the length of $DE$?
Two similar triangles, $\triangle ABC$ and $\triangle DEF$, have areas of $16 \text{ cm}^2$ and $25 \text{ cm}^2$ respectively. If $AB = 4 \text{ cm}$, what is the length of $DE$?
Given that $\cos(x) = \frac{1}{7}$ and $\cos(y) = \frac{13}{14}$, where $x$ and $y$ are acute angles, what is the value of $\cos(x - y)$?
Given that $\cos(x) = \frac{1}{7}$ and $\cos(y) = \frac{13}{14}$, where $x$ and $y$ are acute angles, what is the value of $\cos(x - y)$?
Determine the number of solutions to the equation $\sin(x) = \frac{x}{100}$
Determine the number of solutions to the equation $\sin(x) = \frac{x}{100}$
Consider a triangle in the Cartesian plane with vertices at (0, 0), (5, 0), and (0, 12). What is the sine of the angle at the origin?
Consider a triangle in the Cartesian plane with vertices at (0, 0), (5, 0), and (0, 12). What is the sine of the angle at the origin?
A tower casts a shadow of 30 meters when the angle of elevation of the sun is 60°. What is the height of the tower?
A tower casts a shadow of 30 meters when the angle of elevation of the sun is 60°. What is the height of the tower?
In a $30^\circ$-$60^\circ$-$90^\circ$ triangle, what is the ratio of the side opposite to $30^\circ$ to the hypotenuse?
In a $30^\circ$-$60^\circ$-$90^\circ$ triangle, what is the ratio of the side opposite to $30^\circ$ to the hypotenuse?
In which quadrant of the Cartesian plane is $ an heta$ positive and $\cos heta$ negative?
In which quadrant of the Cartesian plane is $ an heta$ positive and $\cos heta$ negative?
Consider two similar triangles $ riangle ABC$ and $ riangle DEF$. If the ratio of their corresponding heights is $3:5$, what is the ratio of their areas?
Consider two similar triangles $ riangle ABC$ and $ riangle DEF$. If the ratio of their corresponding heights is $3:5$, what is the ratio of their areas?
If in $ riangle ABC$ and $ riangle DEF$, $\angle A = \angle D$ and $\angle B = \angle E$, and $AB = 2DE$, what is the ratio of the area of $ riangle ABC$ to the area of $ riangle DEF$?
If in $ riangle ABC$ and $ riangle DEF$, $\angle A = \angle D$ and $\angle B = \angle E$, and $AB = 2DE$, what is the ratio of the area of $ riangle ABC$ to the area of $ riangle DEF$?
Given that $\sin x = \cos y$ for acute angles $x$ and $y$, what can be concluded about the relationship between $x$ and $y$?
Given that $\sin x = \cos y$ for acute angles $x$ and $y$, what can be concluded about the relationship between $x$ and $y$?
If two triangles are similar, which of the following statements about their corresponding angles is always true?
If two triangles are similar, which of the following statements about their corresponding angles is always true?
In a right-angled triangle $ABC$, where $C$ is the right angle, which side is the hypotenuse?
In a right-angled triangle $ABC$, where $C$ is the right angle, which side is the hypotenuse?
What is the relationship between $an heta$ and $\cot heta$?
What is the relationship between $an heta$ and $\cot heta$?
In which quadrant of the Cartesian plane are both sine and cosine negative?
In which quadrant of the Cartesian plane are both sine and cosine negative?
A surveyor measures the angle of elevation to the top of a building to be $25^\circ$. If the surveyor is standing 50 meters from the base of the building, approximately how tall is the building?
A surveyor measures the angle of elevation to the top of a building to be $25^\circ$. If the surveyor is standing 50 meters from the base of the building, approximately how tall is the building?
Given that $ext{cosec } heta = 2$, what is the value of $\sin heta$?
Given that $ext{cosec } heta = 2$, what is the value of $\sin heta$?
What is the value of $\sin^2(45^\circ) + \cos^2(45^\circ)$?
What is the value of $\sin^2(45^\circ) + \cos^2(45^\circ)$?
If a right triangle has legs of length 3 and 4, what is the cosine of the angle opposite the side of length 3?
If a right triangle has legs of length 3 and 4, what is the cosine of the angle opposite the side of length 3?
Two buildings are 50 meters apart. The angle of depression from the top of the taller building to the top of the shorter building is $20^\circ$. If the taller building is 70 meters tall, how tall is the shorter building?
Two buildings are 50 meters apart. The angle of depression from the top of the taller building to the top of the shorter building is $20^\circ$. If the taller building is 70 meters tall, how tall is the shorter building?
Given a triangle $ABC$ with sides $a$, $b$, and $c$ opposite to angles $A$, $B$, and $C$ respectively, and given that $a = 10$, $b = 12$, and $C = 60^\circ$, find the length of side $c$.
Given a triangle $ABC$ with sides $a$, $b$, and $c$ opposite to angles $A$, $B$, and $C$ respectively, and given that $a = 10$, $b = 12$, and $C = 60^\circ$, find the length of side $c$.
If $ \triangle PQR \sim \triangle XYZ $ and $ \frac{PQ}{XY} = \frac{5}{7} $, what is the value of $ \frac{PR}{XZ} $?
If $ \triangle PQR \sim \triangle XYZ $ and $ \frac{PQ}{XY} = \frac{5}{7} $, what is the value of $ \frac{PR}{XZ} $?
In a right triangle, which trigonometric ratio represents the relationship between the adjacent side and the hypotenuse?
In a right triangle, which trigonometric ratio represents the relationship between the adjacent side and the hypotenuse?
If $ \tan(\theta) = \frac{4}{3} $, what is the value of $ \cot(\theta) $?
If $ \tan(\theta) = \frac{4}{3} $, what is the value of $ \cot(\theta) $?
Given $ \triangle ABC \sim \triangle MNP $, which of the following statements must be true?
Given $ \triangle ABC \sim \triangle MNP $, which of the following statements must be true?
In a right triangle $ ABC $ with right angle at $ C $, if $ AB = 13 $ and $ BC = 5 $, find $ \cos A $.
In a right triangle $ ABC $ with right angle at $ C $, if $ AB = 13 $ and $ BC = 5 $, find $ \cos A $.
If an angle $ \theta $ in the Cartesian plane has its terminal arm in Quadrant III, which of the following is true?
If an angle $ \theta $ in the Cartesian plane has its terminal arm in Quadrant III, which of the following is true?
A ladder 6 meters long leans against a wall, making an angle of 75° with the ground. How high up the wall does the ladder reach?
A ladder 6 meters long leans against a wall, making an angle of 75° with the ground. How high up the wall does the ladder reach?
Given that $ \sin \theta = \frac{1}{2} $ and $ 0^\circ < \theta < 90^\circ $, what is the value of $ \cos \theta $?
Given that $ \sin \theta = \frac{1}{2} $ and $ 0^\circ < \theta < 90^\circ $, what is the value of $ \cos \theta $?
If $ \cos(\theta) = \frac{5}{13} $ and $ \theta $ is in the fourth quadrant, what is $ \tan(\theta) $?
If $ \cos(\theta) = \frac{5}{13} $ and $ \theta $ is in the fourth quadrant, what is $ \tan(\theta) $?
An observer stands 50 meters away from a building and observes the top of the building at an angle of elevation of $30^\circ$. What is the height of the building?
An observer stands 50 meters away from a building and observes the top of the building at an angle of elevation of $30^\circ$. What is the height of the building?
What is the exact value of $ \cos 15^\circ $?
What is the exact value of $ \cos 15^\circ $?
Given $ \sin x = \frac{1}{\sqrt{5}} $ and $ \cos y = \frac{2}{\sqrt{5}} $, where both $ x $ and $ y $ are acute angles, find the value of $ \sin(x + y) $.
Given $ \sin x = \frac{1}{\sqrt{5}} $ and $ \cos y = \frac{2}{\sqrt{5}} $, where both $ x $ and $ y $ are acute angles, find the value of $ \sin(x + y) $.
In triangle $ ABC $, $ a = 5 $, $ b = 7 $, and $ \angle C = 60^\circ $. Find the length of side $ c $.
In triangle $ ABC $, $ a = 5 $, $ b = 7 $, and $ \angle C = 60^\circ $. Find the length of side $ c $.
What is the range of the function $ f(x) = 3 \sin(2x) + 1 $?
What is the range of the function $ f(x) = 3 \sin(2x) + 1 $?
Consider the function $ f(x) = \frac{\sin x}{x} $ for $ x > 0 $. What value does $ f(x) $ approach as $ x $ approaches infinity?
Consider the function $ f(x) = \frac{\sin x}{x} $ for $ x > 0 $. What value does $ f(x) $ approach as $ x $ approaches infinity?
Find the exact value of $ \tan(\frac{5\pi}{12}) $.
Find the exact value of $ \tan(\frac{5\pi}{12}) $.
Given a regular hexagon inscribed in a circle of radius 1, what is the value of the product of the distances from one vertex to all other vertices?
Given a regular hexagon inscribed in a circle of radius 1, what is the value of the product of the distances from one vertex to all other vertices?
Flashcards
Similar Triangles
Similar Triangles
Triangles with equal angles have proportional corresponding sides, regardless of size.
Properties of Similar Triangles
Properties of Similar Triangles
For similar triangles $ \Delta ABC \sim \Delta DEF $, corresponding angles are equal, and $ \frac{AB}{DE} = \frac{BC}{EF} = \frac{AC}{DF} $.
Sides of a Right Triangle
Sides of a Right Triangle
In a right triangle relative to angle $ \theta $, the hypotenuse is opposite the right angle, the opposite is across from $ \theta $, and the adjacent is next to $ \theta $.
Trigonometric Ratios
Trigonometric Ratios
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Reciprocal Trigonometric Ratios
Reciprocal Trigonometric Ratios
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30-60-90 Triangle Ratios
30-60-90 Triangle Ratios
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45-45-90 Triangle Ratios
45-45-90 Triangle Ratios
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Trigonometric Ratios for 30°
Trigonometric Ratios for 30°
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Trigonometric Ratios for 45°
Trigonometric Ratios for 45°
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Trigonometric Ratios for 60°
Trigonometric Ratios for 60°
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Finding Angles
Finding Angles
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Trig Ratios in Cartesian Plane
Trig Ratios in Cartesian Plane
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CAST Diagram
CAST Diagram
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Angle of Elevation
Angle of Elevation
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Angle of Depression
Angle of Depression
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Sine (sin)
Sine (sin)
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Cosine (cos)
Cosine (cos)
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Tangent (tan)
Tangent (tan)
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Reciprocal Trig Functions
Reciprocal Trig Functions
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Tangent in terms of sine and cosine
Tangent in terms of sine and cosine
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Mnemonic Device for CAST Diagram
Mnemonic Device for CAST Diagram
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Trigonometric Ratios in All Quadrants
Trigonometric Ratios in All Quadrants
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Solving for Side Lengths
Solving for Side Lengths
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Ratios of Similar Triangles
Ratios of Similar Triangles
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Cosecant
Cosecant
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Secant
Secant
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Cotangent
Cotangent
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Key Ratios of Similar Triangles
Key Ratios of Similar Triangles
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Soh Cah Toa
Soh Cah Toa
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Reciprocal Relationships
Reciprocal Relationships
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Finding Lengths with Trig Ratios
Finding Lengths with Trig Ratios
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Solve for opposite side
Solve for opposite side
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Quadrant I
Quadrant I
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Quadrant II
Quadrant II
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Quadrant III
Quadrant III
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Quadrant IV
Quadrant IV
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Applications of Trigonometry
Applications of Trigonometry
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Elevation vs. Depression
Elevation vs. Depression
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Study Notes
- Grade 10 trigonometry involves understanding similar triangles, trigonometric ratios, special angles, solving trigonometric equations, trigonometric ratios in the Cartesian plane, and two-dimensional problems.
Similarity of Triangles
- Similarity of triangles is foundational to understanding trigonometry.
- In similar triangles, the ratios of corresponding sides are proportional if the angles are equal.
Ratios of Similar Triangles
- For similar triangles $\Delta ABC$, $\Delta DEF$, and $\Delta GHK$, the ratios of corresponding sides are equal:
- $\frac{AB}{BC} = \frac{DE}{EF} = \frac{GH}{HK}$
- $\frac{AB}{AC} = \frac{DE}{DF} = \frac{GH}{GK}$
- $\frac{BC}{AC} = \frac{EF}{DF} = \frac{HK}{GK}$
- For $\Delta ABC \sim \Delta DEF$, the ratios of corresponding sides are equal
- $\frac{AB}{DE} = \frac{BC}{EF} = \frac{AC}{DF}$
- Corresponding angles in similar triangles are equal:
- $\angle A = \angle D$
- $\angle B = \angle E$
- $\angle C = \angle F$
- Ratios of corresponding sides in similar triangles are equal.
- If the angle remains constant, the ratio remains constant.
Trigonometric Ratios
- Trigonometric ratios are defined using similar right-angled triangles.
- Consider $\triangle ABC$ with a right angle at $C$ and an angle $\theta$ at $A$.
Defining the Trigonometric Ratios
- In relation to $\theta$:
- Hypotenuse: side opposite the right angle.
- Opposite: side opposite $\theta$.
- Adjacent: side next to $\theta$.
- The formulas for the main trigonometric ratios are:
- $\sin \theta = \frac{\text{opposite}}{\text{hypotenuse}}$
- $\cos \theta = \frac{\text{adjacent}}{\text{hypotenuse}}$
- $\tan \theta = \frac{\text{opposite}}{\text{adjacent}}$
- Mnemonic (Soh Cah Toa):
- $\sin \theta = \frac{\text{opposite}}{\text{hypotenuse}}$ (Soh)
- $\cos \theta = \frac{\text{adjacent}}{\text{hypotenuse}}$ (Cah)
- $\tan \theta = \frac{\text{opposite}}{\text{adjacent}}$ (Toa)
Reciprocal Ratios
- Each trigonometric ratio has a reciprocal:
- $\text{cosec } \theta = \frac{1}{\sin \theta} = \frac{\text{hypotenuse}}{\text{opposite}}$
- $\text{sec } \theta = \frac{1}{\cos \theta} = \frac{\text{hypotenuse}}{\text{adjacent}}$
- $\text{cot } \theta = \frac{1}{\tan \theta} = \frac{\text{adjacent}}{\text{opposite}}$
- The relationships between trigonometric ratios and their reciprocals are:
- $\sin \theta \times \text{cosec } \theta = 1$
- $\cos \theta \times \text{sec } \theta = 1$
- $\tan \theta \times \text{cot } \theta = 1$
Special Angles
- Special angles produce simple trigonometric ratios without a calculator.
Special Angle Triangles
- 30°-60°-90° Triangle:
- Hypotenuse: 2
- Opposite 30°: 1
- Opposite 60°: $\sqrt{3}$
- 45°-45°-90° Triangle:
- Hypotenuse: $\sqrt{2}$
- Each leg (opposite 45°): 1
Trigonometric Ratios for Special Angles
- The trigonometric ratios for the special angles are:
- $\sin 30^\circ = \frac{1}{2}$, $\cos 30^\circ = \frac{\sqrt{3}}{2}$, $\tan 30^\circ = \frac{\sqrt{3}}{3}$
- $\sin 45^\circ = \frac{\sqrt{2}}{2}$, $\cos 45^\circ = \frac{\sqrt{2}}{2}$, $\tan 45^\circ = 1$
- $\sin 60^\circ = \frac{\sqrt{3}}{2}$, $\cos 60^\circ = \frac{1}{2}$, $\tan 60^\circ = \sqrt{3}$
Solving Trigonometric Equations
Finding Lengths
- Using trigonometric ratios, unknown side lengths in right-angled triangles can be determined when one angle and one side are known.
- To solve for the opposite side:
- $\text{opposite} = \text{hypotenuse} \times \sin \theta$
Finding Angles
- When two sides are known, angles can be found using inverse trigonometric functions:
- $\theta = \sin^{-1}\left(\frac{\text{opposite}}{\text{hypotenuse}}\right)$
- $\theta = \cos^{-1}\left(\frac{\text{adjacent}}{\text{hypotenuse}}\right)$
- $\theta = \tan^{-1}\left(\frac{\text{opposite}}{\text{adjacent}}\right)$
- Steps to solve for an unknown angle:
- Identify the trigonometric ratio.
- Rearrange to isolate the ratio.
- Use a calculator to find the angle via inverse functions.
Trigonometric Ratios in the Cartesian Plane
Defining Ratios
- Trigonometric ratios extend to any angle in the Cartesian plane using coordinates $(x, y)$ and radius $r = \sqrt{x^2 + y^2}$:
- $\sin \theta = \frac{y}{r}$, $\cos \theta = \frac{x}{r}$, $\tan \theta = \frac{y}{x}$
- $\text{cosec } \theta = \frac{r}{y}$, $\text{sec } \theta = \frac{r}{x}$, $\text{cot } \theta = \frac{x}{y}$
CAST Diagram
- The CAST diagram defines signs of trigonometric functions in each quadrant:
- Quadrant I (0°–90°): All positive
- Quadrant II (90°–180°): $\sin$ and $\text{cosec}$ positive
- Quadrant III (180°–270°): $\tan$ and $\cot$ positive
- Quadrant IV (270°–360°): $\cos$ and $\sec$ positive
Special Angles in the Cartesian Plane
- The trigonometric ratios for the special angles are:
- $\sin 0^\circ = 0$, $\cos 0^\circ = 1$, $\tan 0^\circ = 0$
- $\sin 90^\circ = 1$, $\cos 90^\circ = 0$, $\tan 90^\circ = \text{undefined}$
Two-Dimensional Problems
Applications
- Trigonometry is used to solve practical problems involving right-angled triangles, such as construction and navigation.
- Angle of Elevation:
- The angle above the horizontal when looking up at an object.
- Angle of Depression:
- The angle below the horizontal when looking down at an object.
- The angle of elevation from one point equals the angle of depression from the corresponding point.
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