Given a right angled triangle XYZ with angles Y = π/2 and X = 0.29, side z = 5.0 mm. Find side y. Give your answer in mm to 2 decimal places.
Understand the Problem
The question asks us to find the length of side y of a right-angled triangle XYZ, given the angles Y and X, and the length of side z. We will use trigonometric ratios to solve for y.
Answer
$1.95 \, \text{mm}$
Answer for screen readers
The length of side $y$ is approximately $1.95 , \text{mm}$.
Steps to Solve
- Identify the angles and sides Given the angles in triangle XYZ:
- Angle $Y = \frac{\pi}{2}$ (90 degrees)
- Angle $X = 0.29$ radians
You can find angle $Z$ using the property that the sum of angles in a triangle is $\pi$ radians (or 180 degrees): $$ Z = \pi - (Y + X) = \pi - \left(\frac{\pi}{2} + 0.29\right) $$
- Calculate angle Z Now, substitute the values: $$ Z = \pi - \left(\frac{\pi}{2} + 0.29\right) $$
This gives us: $$ Z \approx 2.851 - 0.29 \approx 2.561 $$ \text{ radians}
- Use the sine rule Since we want to find side $y$ opposite angle $Y$, we can apply the sine rule, which states: $$ \frac{y}{\sin(Y)} = \frac{z}{\sin(Z)} $$
Rearranging gives: $$ y = z \cdot \frac{\sin(Y)}{\sin(Z)} $$
- Substitute values Substituting the known values into the equation:
- $z = 5.0 , \text{mm}$
- $Y = \frac{\pi}{2}$
Thus: $$ y = 5.0 \cdot \frac{\sin\left(\frac{\pi}{2}\right)}{\sin(2.561)} $$
- Calculate y Now we can compute: $$ y = 5.0 \cdot \frac{1}{\sin(2.561)} $$
Using a calculator, find $\sin(2.561)$ and then compute $y$.
The length of side $y$ is approximately $1.95 , \text{mm}$.
More Information
The sine rule is particularly useful in non-right triangle problems, but we used it effectively in this right-angled triangle by finding the angles first.
Tips
- A common mistake is incorrectly calculating angle $Z$. Ensure the angles add up to $\pi$ radians.
- Another mistake is not using the correct sides in the sine rule, so always pay attention to which side corresponds to which angle.
AI-generated content may contain errors. Please verify critical information