Find the circumference and area of a circle with diameter 12 ft. Express your answer in terms of π.

Question

I've tried working with this problem a few times but can't seem to figure it out.

Answer 1

Area of a circle = π r²

r = 1/2 d or radius is 1/2 the diameter = 1/2 x 12 ft = 6 ft

Area = (π)(6 ft)²  = (π)(36 ft) = 36π ft²

 

Circumference of a circle = 2 π r = (2)(π)(6 ft) = 12π ft

Answer 2

The question is just an application of the formulas for finding the circumference and area a circle. Expressing your answer in terms of of pie, just means that you don't have to actually plug a value in for pie. Just leave the symbol as part of the answer. Otherwise, just remember that the circumference of a circle is a line segment that goes from one edge of a circle to the other, and passes straight through the center. A radius only travels half this distance, from the center of the circle to the edge. (Hint: if you need the radius of a circle you can calculate it using the diameter)