# Lesson and Practice: Circle and Coordinate Geometry

Discover how to write the equation of a circle given its center and radius, and how to find center and radius given the general equation of a circle. Explore the applet, then answer the questions displayed below.

Select the option "Circle - given center and radius" in the app above, then drag the center C at (0,0). Use the slider to display different circles with center at (0,0). What is the equation of a circle with center at (0,0) and radius r?

A circle with center C=(0,0) passes through P=(2,3). What is the equation of the circle?

Given A=(-8,-3) and B=(2, 5), write the equation of the circle with diameter AB.

Select the option "Circle - general equation" in the applet above and use the sliders to explore the equation and the corresponding graph. When ...

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