### Home > MC1 > Chapter 9 > Lesson 9.3.1 > Problem9-124

9-124.

Find the circumference of each of the circles described below.

1. Radius of $3$ inches

Recall the diagram from the Math Notes box from Lesson 9.3.1 below.
Also recall that the same Math Notes box says that the circumference $= 2π\left(\text{radius}\right)$.

$2π\left(3 \text{ inches}\right) = 6π ≈ 18.84$ inches

2. Diameter of $27$ cm

Refer to the diagram from part (a) and recall that the circumference = π(diameter).

$27π$
To get an approximate decimal answer, round π so that it equals $3.14$.