# How do you write the standard form of the equation of the circle with radius 8 and center at (0,0)?

Jun 29, 2018

${x}^{2} + {y}^{2} = 64$

#### Explanation:

The standard equation of a circle with center $\left(h , k\right)$ is

${\left(x - h\right)}^{2} + {\left(y - k\right)}^{2} = {r}^{2}$, with radius $r$.

When we have a circle centered at the origin, this equation turns into

${x}^{2} + {y}^{2} = {r}^{2}$

Notice that our $\left(h , k\right)$ goes away. We know that $r = 8$, so we can plug this in. We get

${x}^{2} + {y}^{2} = {8}^{2}$

$\implies {x}^{2} + {y}^{2} = 64$

Hope this helps!