Problem 13 · 2009 Math Kangaroo
Hard
Geometry & Measurement
perimeter
The length of a rectangle is 8 cm. The width is half as long. How long are the sides of a square that has the same perimeter as the rectangle?
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Answer: B — 6 cm
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Hint 1 of 2
Find the rectangle's perimeter first.
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Hint 2 of 2
A square with the same perimeter has all four sides equal, so divide by 4.
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Approach: equal perimeters
- The rectangle is 8 cm long and half as wide, so 4 cm wide.
- Its perimeter is 2 × (8 + 4) = 24 cm.
- A square with perimeter 24 cm has side 24 ÷ 4 = 6 cm.
- So the square's side is 6 cm.
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