Question

The diameter of a circle is 18 in. Find its area in terms of π π.

Answer 1

Answer: 81 π.

Step-by-step explanation: To find the area of a circle, you need to multiply the circle's radius squared by pi.  However, this problem is in terms of pi, so we're just going to find the radius squared.  We're given the diameter, but we can simply cut it in half since the radius is half the diameter.  The diameter for this circle is 18, so divide 18 by 2, and 9 is your radius.  9^2 is 81, so 81 π is your answer in terms of pi because when you find the radius squared, you put pi next to it.

Have a great day! :)

Answer 2

Answer: the area is 81π

Step-by-step explanation:

The formula is A=πr

^{2}

The raidius would be 9 (18/2)

A=π9^{2} 

π x 9^{2} = 81π

Decimal form: 254.469004941