You may also like

problem icon

Consecutive Numbers

An investigation involving adding and subtracting sets of consecutive numbers. Lots to find out, lots to explore.

problem icon

Circles Ad Infinitum

A circle is inscribed in an equilateral triangle. Smaller circles touch it and the sides of the triangle, the process continuing indefinitely. What is the sum of the areas of all the circles?

problem icon

Golden Thoughts

Rectangle PQRS has X and Y on the edges. Triangles PQY, YRX and XSP have equal areas. Prove X and Y divide the sides of PQRS in the golden ratio.

Weekly Problem 47 - 2011

Challenge Level: Challenge Level:1

Each pentagon has a turn of 36o to pack against its neighbour.

Therefore it will take 10 (x36o) turns to complete a full-turn, i.e. 10 pentagons

Therefore 7 more pentagons are needed.

chain of 10 pentagons around a circle

This problem is taken from the UKMT Mathematical Challenges.

View the previous week's solution
View the current weekly problem