Question

Please please please help. thank you.

Answer 1

Lets get started :)


The First question:
Diameter = 20 ft
Radius = $\frac{1}{2}$ of 20 (diameter) = 20 ft

Area formula of a circle is
A = $\pi$r²
    =$\pi$(10)²
    =100$\pi$ ft²
    ≈ 314 ft²

The answer will be the second option

The Second question:
radius of circle = 12mm  divided into 20 sectors area

A = $\pi$r²
   = $\pi$(12)²
   = 144$\pi$ ft²

Divide into 20 equal sector areas = $\frac{144 \pi }{20} = 7.2 \pi$

≈ 22.6 mm²

Your answer will be the third option

The Third Question:

90°, sector area = 36$\pi$ , Radius = ?

$\frac{angle}{360} = \frac{sector}{ \pi (r)^2}$
$\frac{90}{360} = \frac{36 \pi }{ \pi r^2}$
$\pi$ and $\pi$ cancels out

We can now cross multiply
360 × 36 = 90r²
12960 = 90r²

Divide by 90 on either side

$\frac{12960}{90} = \frac{90r^2}{90}$
144 = r²

Take squareroot 
 $\sqrt{144} = x$
x = 12 in

Your answer will be the third option