Question

Find the area of washers whose external and internal diameter are 1.2m and 0.9m

Answer 1

0.49 m²

Explanation:

The area (A) is calculated using A = πr² ( r is the radius )

A = external area - internal area

external radius =
`(1.2)/(2)` = 0.6

internal radius =
`(0.9)/(2)` = 0.45

A = π(0.6² - 0.45²)

= π(0.36 - 0.2025) = 0.1575π ≈ 0.49 m²