Question

A semicircle has an area of 76.97 squared km. Find it’s radius

Answer 1

7 km

Explanation:

Substitute:

The equation for area of a semi-circle is
`(r^(2)\pi )/(2)`

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

76.97 =
`(r^(2)\pi )/(2)`

Multiply by 2 on both sides:

2(76.97) = (
`(r^(2)\pi )/(2)`)2

153.94 =
`r^(2) \pi`

Divide by pi on both sides:

153.94 =
`r^(2) \pi`

/pi /pi

49.03 ≈
`r^(2)`

Find the square root:

`√(49.03) =\sqrt{r^(2) }`

7 = r