# The points (-2,5) and (9,-3) are the endpoints of the diameter of a circle, how do you find the length of the radius of the circle?

Nov 7, 2015

Radius of circle $\cong 6.80$

#### Explanation:

(see rough diagram below)
The diameter of the circle is given by the Pythagorean theorem as
$\textcolor{w h i t e}{\text{XXX}} \sqrt{{8}^{2} + {11}^{2}}$

color(white)("XXX")=sqrt(185

$\textcolor{w h i t e}{\text{XXX}} \cong 13.60$ (using calculator)

The radius is half the length of the diameter.