ACT Math: Plane Geometry Drill 5, Problem 1. What is the area of the circle?
|ACT Math||Plane Geometry|
|ACT Mathematics||Plane Geometry|
|Circles||Equations of Circles|
|Foreign Language||Arabic Subtitled|
|Product Type||ACT Math|
Hopefully, we remember the formula for the circumference of a circle: Diameter times
We're told that a circle has a circumference
of 12 pi...which means the diameter of this circle is 12.
If the diameter is 12, the radius is exactly half of that... 6.
The area of a circle is equal to π times radius squared,
and now that we have the radius, we just have to plug in that value.
6 squared is 36...so we get 36π as our answer, which is choice C.