Question

A patio in the shape of a semicircle has a diameter of 21 ft. What is the approximate area of the patio, rounded to the nearest square foot? Use 3.14 to approximate pi star times pi.

Answer 1

The formula of the area of a semi circle is half the area of the circle


`( \pi r^2)/(2)`

Diameter = 21 ft
Radius =
`(d)/(2)` =
`(21)/(2)` = 10.5 ft

Area =
`( \pi (10.5)^2)/(2)`
=
`(110.25 \pi )/(2)`
=
`(110.25 * 3.14)/(2)` (3.14 as
`\pi`)
=
`(346.185)/(2)`
=173.0925 ft² ≈ 173.1 ft² ≈ 173 ft²
To the nearest square foot : 173 ft²