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Problem 350

Geometry Difficulty 2.4 Multiple choice CEMC Pascal · Canada · 2016

In the diagram, the area of square QRSTQRST is 36. Also, the length of PQPQ is one-half of the length of QRQR.


What is the perimeter of rectangle PRSUPRSU?

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Official solution

Since square QRSTQRST has area 36, then its side length is 36=6\sqrt{36}=6.

Therefore, QR=6QR = 6 and RS=6RS=6.

Since PQ=12QRPQ = \frac{1}{2}QR, then PQ=3PQ = 3.

Now rectangle PRSUPRSU has height RS=6RS = 6 and width PR=PQ+QR=3+6=9PR = PQ + QR = 3+6=9.

Therefore, the perimeter of PRSUPRSU is 2(6)+2(9)=12+18=302(6) + 2(9) = 12+18=30.

Source: CEMC, University of Waterloo, licensed CC-BY-NC-4.0. Statement reproduced verbatim; metadata (topic, difficulty, ordering) added by this project.