## Basic College Mathematics (10th Edition)

The circumference of the circle is $5.7$ km.
1. Find the diameter of the circle $= 0.9 \times 2$ $= 1.8$ km 2. Using the formula $= diameter \times \pi$, find the circumference $= 1.8 \times 3.14$ $= 5.652$ km $= 5.7$ km