Question

The circumference of a dinner plate is 15.7 inches. what is the radius?

Answer 1

`The\ circumference\ of\ a\ circle:C=2\pi r\ \ \ \ \ \ (r-a\ radius)\\\\C=15.7\to2\pi r=15.7\ \ \ \ |divide\ both\ sides\ by\ 2\\\\\pi r=7.85\ \ \ \ |divide\ both\ sides\ by\ \pi\\\\r=(7.85)/(\pi)\ (in)\\\\\pi\approx3.14\to r\approx(7.85)/(3.14)=\boxed{2.5\ (in)}`