### Home > GC > Chapter 12 > Lesson 12.1.2 > Problem 12-20

12-20.

The formula for the circumference of a circle is 2*πr*.

28 = 2*r*

28π = 2π*r*

*r* = 14

Base = *r*²π

= 14²π

= 196π

≈ 3694.5 in³

12-20.

The formula for the circumference of a circle is 2*πr*.

28 = 2*r*

28π = 2π*r*

*r* = 14

Base = *r*²π

= 14²π

= 196π

≈ 3694.5 in³