Formula for finding the area of a circle: 
We need to radius but we only have the diameter.
Luckily for us, if you have the diameter, you have the radius.
Because the radius is the diameter over 2.
10 / 2 = 5
Plug in the values.
A = (3.14)5^2
A = (3.14)25
A = 78.5
So, the answer is 78.5.
We need to radius but we only have the diameter.
Luckily for us, if you have the diameter, you have the radius.
Because the radius is the diameter over 2.
10 / 2 = 5
Plug in the values.
A = (3.14)5^2
A = (3.14)25
A = 78.5
So, the answer is 78.5.