Question

A car has two wipers which do not overlap. Each wiper has a blade of length $25cm$ sweeping through an angle of ${115}^{\circ }$. Find the total area cleaned at each sweep of the blades

Answer 1

Total area cleaned by 2 wipers

$=2\times$ area cleaned by 1 wiper

$=2\times$ area of sector with ${115}^{\circ }$

$=2\times \frac{\theta }{{360}^{\circ }}\times \pi r^2$

$=2\times \frac{{115}^{\circ }}{{360}^{\circ }}\times \frac{22}{7}\times {25}^2$

Therefore area cleaned by wipers $=\frac{158125}{126}c{m}^2=1254.96$