Question

If a circle has a diameter of $10$ inches, what is the circumference?

Answer 1

$10\pi$
Explantion:
The equation for circumference is $2\pi r$
You are given the diameter, which is double that of the radius. Therefore, the radius is $\frac{10}{2}=5$ inches
Substituting this into the equation will give you
$2\pi .5=10\pi$