# Equation of a circle

4 videos

3 skills

You know that a circle can be viewed as the set of all points that whose distance from the center is equal to the radius. In this tutorial, we use this information and the Pythagorean Theorem to derive the equation of a circle.

### Equation for a circle using the Pythagorean Theorem

VIDEO
6:19 minutes

### Pythagorean theorem and radii of circles

VIDEO
5:53 minutes

### Pythagorean theorem and the equation of a circle

PRACTICE PROBLEMS

### Radius and center for a circle equation in standard form

VIDEO
3:51 minutes

### Equation of a circle in factored form

PRACTICE PROBLEMS

Find the center and radius of a circle given the equation in factored form.

### Completing the square to write equation in standard form of a circle

VIDEO
4:20 minutes

### Equation of a circle in non-factored form

PRACTICE PROBLEMS

Find the center and radius of a circle given the equation in unfactored form.