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Problem 48

Geometry Difficulty 1.0 Find the answer CEMC Fermat · Canada · 2020

The points O(0,0)O(0, 0), P(0,3)P(0,3), QQ, and R(5,0)R(5,0) form a rectangle, as shown.

The coordinates of QQ are

(5,5)(5,5)
(5,3)(5,3)
(3,3)(3,3)
(2.5,1.5)(2.5,1.5)
(0,5)(0,5)

A number or a short expression. Fractions can be typed as 3/2, and spacing doesn't matter.

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Official solutions — 2

Solution 1

Since OPQROPQR is a rectangle with two sides on the axes, then its sides are horizontal and vertical.

Since PQPQ is horizontal, the yy-coordinate of QQ is the same as the yy-coordinate of PP, which is 3.

Since QRQR is vertical, the xx-coordinate of QQ is the same as the xx-coordinate of RR, which is 5.

Therefore, the coordinates of QQ are (5,3)(5,3).

Solution 2

Since OPQROPQR is a rectangle with two sides on the axes, then its sides are horizontal and vertical.
Since PQPQ is horizontal, the yy-coordinate of QQ is the same as the yy-coordinate of PP, which is 3.
Since QRQR is vertical, the xx-coordinate of QQ is the same as the xx-coordinate of RR, which is 5.
Therefore, the coordinates of QQ are (5,3)(5,3).

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