Question

In the figure shown ,there are four blades of same size of a circular fan of radius $20cm$. Find the area of all blades together.

Answer 1

Each angle$=\frac{360}{8}=45°$

So area of 4 blades$=4\times \frac{\theta }{360}\times \pi r^2$

$=4\times \frac{45}{360}\times \pi {20}^2$

$=628c{m}^2$