### Home > A2C > Chapter 5 > Lesson 5.2.1 > Problem5-72

5-72.

Give the equation of each circle below in graphing form.

1. A circle with center $\left(0, 0\right)$ and radius $6$.

Remember the general equation for a circle is $\left(x − h\right)^{2} + \left(y − k\right)^{2} = r^{2}$ where $\left(h, k\right)$ is the center.

2. A circle with center $\left(2, −3\right)$ and radius $6$.

See part (a).

3. A circle with equation $x^{2} + y^{2} − 8x + 10y + 5 = 0$.

Complete the squares for x and y.

Rearrange the equation:
$x^{2} − 8x +\text{ _______} + y^{2} + 10y + \text{_______} = −5 + \text{_______} + \text{_______}$

$\left(x − 4\right)^{2} + \left(y + 5\right)^{2} = 36$

Use the eTool below to graph the equations for each part.
Click the link at right for the full version of the eTool: A2C 5-72 HW eTool