Problem:
What is the area of the shaded pinwheel shown in the grid?
Answer Choices:
A.
B.
C.
D.
E.
Solution:
Find the area of the unshaded portion of the grid, then subtract the unshaded area from the total area of the grid. The unshaded triangle in the middle of the top of the grid has a base of and an altitude of . The four unshaded triangles have a total area of square units. The four corner squares are also unshaded, so the shaded pinwheel has an area of square units.
Answer: .
The problems on this page are the property of the MAA's American Mathematics Competitions