Question

Hello I'm stuck on this homework problem and need help thank you

Answer 1

Given:

Inner radius circle = 10yd

Outer radius circle = 14 yd

One gallon of coating can cover = 4

Find-: How many gallons of coating do we need?

Sol:

The area of a circle is:

`A=\pi r^2`

The area of the outer circle is:

`\begin{gathered} A=\pi r^2 \\ \\ =\pi(14)^2 \\ \\ =196\pi \end{gathered}`

The area of the inner circle:

`\begin{gathered} A=\pi r^2 \\ \\ A=\pi(10)^2 \\ \\ A=100\pi \end{gathered}`

So the pool area is:

`\begin{gathered} \text{ Area of pool = Area of outer circle - area of inner circle} \\ \\ =196\pi-100\pi \\ \\ =96\pi \end{gathered}`

If one gallon of coating covers 4.

`\begin{gathered} =(96\pi)/(4) \\ \\ =24\pi \\ \\ =75.4 \end{gathered}`

So 75 gallons use for coating.