Finding the Center and Radius of a Circle Using the Equation

This video tutorial teaches how to find the center and radius of a circle using its equation. It begins with an introduction to the graph of a circle, explaining the center and radius. The standard form of a circle's equation is then discussed, highlighting the significance of h, k, and r. Two examples are provided to demonstrate how to rewrite equations into standard form and identify the center and radius.

What is the center of a circle in a graph?

• The diameter of the circle

• A line from the center to the edge

• A point around which the radius rotates

• The circumference of the circle

In the standard form of a circle's equation, what do the variables h and k represent?

• The radius of the circle

• The circumference of the circle

• The center of the circle

• The diameter of the circle

How is the radius represented in the standard form of a circle's equation?

• As r squared

• As r

• As h squared

• As k squared

If an equation is x minus 3 squared plus y plus 6 squared equals 81, what is the center of the circle?

• (3, -6)

• (3, 6)

• (-3, -6)

• (-3, 6)

For the equation x squared plus y minus 3 squared equals 30, what is the radius of the circle?

• 3

• Square root of 30

• 30

• 15