How do you find the circumference and area of a circle with diameter of 12 inches?

2 Answers

The circumference of a circle is #S=2pir# where r =radius
The area of cirlce is #A=pir^2#
The diameter is twice the radius #d=2r=>r=6#

So the circumference is #S=12pi# inches
And the area #A=36pi#

Sep 20, 2015

Answer:

#C=38"in"#
#A=113"in"^2#

Explanation:

To find circumference when diameter is known, use the equation #C=pixxd#

#C=pi*12"in"=38"in"#

To find the area of a circle, use the formula #A=pi*r^2#, where #r# is the radius, which half of the diameter. #r=1/2d=1/2*12"in"=6"in"#.

#A=pi*(6"in")^2"="113"in"^2#