You may also like

problem icon

14 Divisors

What is the smallest number with exactly 14 divisors?

problem icon

Summing Consecutive Numbers

Many numbers can be expressed as the sum of two or more consecutive integers. For example, 15=7+8 and 10=1+2+3+4. Can you say which numbers can be expressed in this way?

problem icon

Rule of Three

If it takes four men one day to build a wall, how long does it take 60,000 men to build a similar wall?

Weekly Problem 44 - 2010

Stage: 3 Short Challenge Level: Challenge Level:1

The diagram shows a regular 9-sided polygon (a nonagon or an enneagon) with two of the sides extended to meet at the point X.

What is the size of the acute angle at X?




If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.

 

This problem is taken from the UKMT Mathematical Challenges.

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