Library / UKMT Pink Kangaroo /112 of 220

UKMT Pink Kangaroo, 2020

Geometry Difficulty 2.0 Junior Find the answer United Kingdom

An isosceles triangle has a side of length $20$ cm. Of the remaining two side-lengths, one is equal to two-fifths of the other. What is the length of the perimeter of this triangle?

(A) $36$ cm (B) $48$ cm (C) $60$ cm (D) $90$ cm (E) $120$ cm

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.