# What is the center and radius of the circle with equation x^2 + y^2 – 8x – 20y + 80 = 0?

Nov 7, 2016

Centre$= \left(4 , 10\right)$ radius$= 6$

#### Explanation:

It's enough to complete the squares....
${x}^{2} - 8 x + 16 + {y}^{2} - 20 y + 100 - 16 - 100 + 80 = 0$
${\left(x - 4\right)}^{2} + {\left(y - 10\right)}^{2} = 36$