Maths Olympiad Prep

Library / UKMT Maclaurin Olympiad /6 of 18

UKMT Maclaurin Olympiad, 2026

Geometry Difficulty 3.0 AMC 10/12 Prove it United Kingdom

A square ABCDABCD has each side of length 1. XX lies on ABAB and YY lies on ADAD with AX=xAX = x, AY=yAY = y and x<yx < y. Triangle AXYAXY is removed to leave a pentagon BCDYXBCDYX. The perimeter of BCDYXBCDYX is 2930\frac{29}{30} of the perimeter of ABCDABCD. The area of BCDYXBCDYX is also 2930\frac{29}{30} of the area of ABCDABCD. Find the length of AXAX.

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.