Checkpoint: Circles Solution

Write the equation of each circle in the form ${(x - h)}^{2} + {(y - k)}^{2} = r^{2}$ .

Circle G

$(- 4, 3), r = 3 {(x - (- 4))}^{2} + {(y - 3)}^{2} = 3^{2} {(x + 4)}^{2} + {(y - 3)}^{2} = 9$

Circle H

$(2, - 3), r = 5 {(x - 2)}^{2} + {(y - (- 3))}^{2} = 5^{2} {(x - 2)}^{2} + {(y + 3)}^{2} = 25$

Note

Q: What is the diameter of circle G and circle H ?

A: Circle G has a diameter of 6. Circle H has a diameter of 10.

Q: How can you find the length of the radius if it is written as a simplified value?

A: Take the square root.