ACT Math 5.1 Plane Geometry

ACT Math: Plane Geometry Drill 5, Problem 1. What is the area of the circle?

ACT MathPlane Geometry
ACT MathematicsPlane Geometry
CirclesEquations of Circles
Coordinate GeometryConics
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Plane GeometryArea
Product TypeACT Math

Transcript

00:19

Hopefully, we remember the formula for the circumference of a circle: Diameter times

00:24

We're told that a circle has a circumference

00:26

of 12 pi...which means the diameter of this circle is 12.

00:31

If the diameter is 12, the radius is exactly half of that... 6.

00:36

The area of a circle is equal to π times radius squared,

00:39

and now that we have the radius, we just have to plug in that value.

00:44

6 squared is 36...so we get 36π as our answer, which is choice C.