Question

The diagram shows a windscreen wiper cleaning a car windscreen. What is the length of the arc swept out? What area of the windscreen is not cleaned?

Answer 1

Find the area of the windscreen:

Area = Length x Breadth

Area = 55 x 100 = 5500 cm²

Find the area of covered by the wiper:

Given radian = 8π/9 and radius = 45

Area = 1/2 r² ∅

Area = 1/2 (45)² (8π/9)

Area = 2827 cm²

Find the area not covered by the wiper:

5500 - 2827 = 2173 cm²

Answer: 2173 cm² is not cleaned.

Answer 2

Answer:

Find the area of the windscreen:

Area Length x Breadth

Area 55 x 100 = 5500 cm²

Find the area of covered by the wiper:

Given radian = 8/9 and radius = 45

Area = 1/2 r2 Ø

Area = 1/2 (45)2 (8π/9)

Area = 2827 cm²

Find the area not covered by the wiper:

55002827 = 2173 cm²

Answer: 2173 cm² is not cleaned.