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2022 Math Kangaroo

Problem 3

Problem 3 · 2022 Math Kangaroo Medium
Geometry & Measurement perimeter

An equilateral triangle with side length 12 has the same perimeter as a square with side length x. What is the value of x?

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Answer: A — 9
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Hint 1 of 2
Equal perimeters is the key link between the two shapes.
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Hint 2 of 2
Set the triangle's perimeter equal to the square's perimeter.
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Approach: equate perimeters
  1. Triangle perimeter = 3 * 12 = 36.
  2. Square perimeter = 4x, so 4x = 36.
  3. x = 9.
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