Geometry and TrigonometryVery hardPerimeter of a similar triangle from one pair of sides
Geometry and Trigonometry practice question
Triangle PQR has sides 4, 5, and 6. Triangle XYZ is similar to PQR, and its shortest side has length 6. What is the perimeter of triangle XYZ?
Answer: 22.5 or 45/2
The scale factor is 6/4 = 1.5, so the perimeter is 1.5 × 15 = 22.5.
Common wrong answers
- If you answered 15
- 15 is PQR's perimeter.
- If you answered 17
- 17 adds 2 to each side instead of scaling.
- If you answered 30
- 30 doubles PQR's perimeter.
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