You may also like

problem icon

Rudolff's Problem

A group of 20 people pay a total of £20 to see an exhibition. The admission price is £3 for men, £2 for women and 50p for children. How many men, women and children are there in the group?

problem icon

Medallions

Three circular medallions fit in a rectangular box. Can you find the radius of the largest one?

problem icon

Square Mean

Is the mean of the squares of two numbers greater than, or less than, the square of their means?

Building Tetrahedra

Stage: 4 Challenge Level: Challenge Level:2 Challenge Level:2

Imagine putting together two triangles with a perimeter of 20, edge to edge. 

Can you now add a third triangle with the same perimeter?

And a fourth?