Find the area and the circumference of a circle with a diameter of 7 ft. Use the value 3.14 for pi, and do not round your answers.

Question

Be sure to include correct units in your answer. 

Answer 1

the circumference of a circle could either be 2*pi*r or pi*d

area of a circle is pi*r²

the diameter of a circle is 2*r

 

Therefore, radius is 3.5 ft

 

circumference = (7)(3.14) = 21.98 or 2(3.14)(3.5) = 21.98

area = (3.14)(3.5)² = 38.465

Answer 2

A = πd²/4

 

C = πd

 

You have values for both d and π.  Just plug in the numbers and get A if ft² and C in ft.  That is all there is to it.