Question

What is the approximate area of the shaded region?

A.178.5 square centimeters
B. 100 square centimeters
C. 78.5 square centimeters
D. 21.5 square centimeters

Answer 1

If we consider that the figure is a square and the white region of the figure is a circle, the area of the shaded region is:


`S=S_(square)-S_(circle)=\ell^2-\pi r^2=10^2-\pi5^2=100-25\pi\\\\ S\approx100-25\cdot3.14=100-78.5\\\\ \boxed{S\approx21.5~cm^2}\Longrightarrow Alternative~D`