Problem 3 · 2018 Math Kangaroo
Easy
Geometry & Measurement
perimeter
A triangle ABC has side lengths 6 cm, 10 cm and 11 cm. An equilateral triangle XYZ has the same perimeter as triangle ABC. What is the side length of triangle XYZ?
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Answer: B — 9 cm
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Hint 1 of 2
Equal perimeters means the two triangles have the same total side length.
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Hint 2 of 2
Find the perimeter of ABC, then split it into three equal sides.
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Approach: match perimeters, then divide by 3
- Perimeter of ABC = 6 + 10 + 11 = 27 cm.
- The equilateral triangle has the same perimeter, so each side = 27 : 3 = 9 cm.
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