If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.
The diagram shows a triangle and three circles whose centres are at the vertices of the triangle. The area of the triangle is $80 cm^2$ and each of the circles has radius $2cm$. What is the area, in $cm^2$, of the shaded area?
If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.