Podcast
Questions and Answers
What is the approximate length of side DE of triangle DEF?
What is the approximate length of side DE of triangle DEF?
- 19.21
- 17.46 (correct)
- 52.79
- 16.12
Which expression correctly calculates the length of side EF?
Which expression correctly calculates the length of side EF?
- $\sqrt{(-7 - (-9))^2 + (-7 - 9)^2}$
- $\sqrt{(8 - 9)^2 + (5 - 7)^2}$
- $\sqrt{(8 - (-9))^2 + (5 - 9)^2}$
- $\sqrt{(8 - (-7))^2 + (5 - (-7))^2}$ (correct)
If the coordinates of D were changed to (-8, 8) and all other coordinates were the same, which side's length would be most affected (increased or decreased) ?
If the coordinates of D were changed to (-8, 8) and all other coordinates were the same, which side's length would be most affected (increased or decreased) ?
- All sides would be equally affected.
- FD
- EF
- DE (correct)
What is the perimeter of triangle DEF, rounded to the nearest tenth?
What is the perimeter of triangle DEF, rounded to the nearest tenth?
What is the distance between points F and D calculated as?
What is the distance between points F and D calculated as?
Flashcards
Distance Formula
Distance Formula
The distance between two points in a coordinate plane.
Perimeter of a triangle
Perimeter of a triangle
The total length of all sides of a triangle added together.
Triangle
Triangle
A three-sided closed figure.
Coordinates of a point
Coordinates of a point
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Distance formula
Distance formula
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Study Notes
Coordinates of the vertices
- D(-9, 9)
- E(8, 5)
- F(-7, -7)
Calculating the lengths of the sides
- DE: √[(8 - (-9))² + (5 - 9)²] = √(17² + (-4)²) = √289 + 16 = √305 ≈ 17.46
- EF: √[(8 - (-7))² + (5 - (-7))²] = √(15² + 12²) = √225 + 144 = √369 ≈ 19.21
- FD: √[(-7 - (-9))² + (-7 - 9)²] =√(2² + (-16)²) =√4 + 256 =√260 ≈ 16.12
Perimeter of ΔDEF
-
Perimeter = DE + EF + FD = 17.46 + 19.21 + 16.12 ≈ 52.79
-
Perimeter ≈ 52.8 units
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Description
Test your understanding of the properties of triangle DEF by calculating the lengths of its sides and determining the perimeter. This quiz covers the application of the distance formula in coordinate geometry. Perfect for students studying geometry concepts in a classroom setting.
