Maths Olympiad Prep

Library / UKMT Grey Kangaroo /218 of 242

UKMT Grey Kangaroo, 2025

Geometry Difficulty 3.0 AMC 10/12 Find the answer United Kingdom

In the rectangle PQRSPQRS, the points TT and UU are marked on side SRSR as shown, so that ∠RUQ=∠STP=45∘\angle RUQ = \angle STP = 45^\circ and PQ+UT=20cmPQ + UT = 20\text{cm}. What is the length of QRQR?

(A) 4 cm4\text{ cm} (B) 6 cm6\text{ cm} (C) 8 cm8\text{ cm} (D) 10 cm10\text{ cm} (E) 12 cm12\text{ cm}

Figure for this problem

We don't reproduce this publisher's solutions. Their own solution is here — work the problem first.
Want a route through all this instead of an archive? The track puts 2,604 problems in a working order, from Junior Challenge level to the IMO shortlist.

Source: UK Mathematics Trust, licensed © UK Mathematics Trust; past papers published free at ukmt.org.uk. Statement reproduced verbatim; metadata (topic, difficulty) added by this project. Solutions are the publisher's, linked not copied.