# What is the area of a circle with a diameter of 4, 9, and 11 ft?

##### 1 Answer

Mar 29, 2018

The areas in

# d = 4 => A = 4pi#

# d = 9 => A = 81/4pi#

# d = 11 => A = 121/4pi#

#### Explanation:

The area of a circle of radius

# A = pir^2 #

If the diameter is

# A = pi(d/2)^2 = (pid^2)/4#

Thus, we have:

# d = 4 => A = (pi4^2)/4 =4pi#

# d = 9 => A = (pi9^2)/4 =81/4pi#

# d = 11 => A = (pi11^2)/4 =121/4pi#