Question

find the area of each circle. write your answer using π.

1. 20 yd
2. 8 ft

Explanation:

Step1: Recall area formula

The formula for the area of a circle is $A = \pi r^{2}$, where $r$ is the radius of the circle.

Step2: Find radius for first circle

The diameter of the first circle is $d = 20$ yd. Since $r=\frac{d}{2}$, then $r_1=\frac{20}{2}=10$ yd.

Step3: Calculate area of first circle

Substitute $r_1 = 10$ yd into the area formula: $A_1=\pi\times(10)^{2}=100\pi$ yd².

Step4: Find radius for second circle

The radius of the second circle is given as $r_2 = 8$ ft.

Step5: Calculate area of second circle

Substitute $r_2 = 8$ ft into the area formula: $A_2=\pi\times(8)^{2}=64\pi$ ft².

Answer:

The area of the first - circle is $100\pi$ yd² and the area of the second - circle is $64\pi$ ft².