Equation of a Circle

Using the following equations, find the center and radius of the circle:

  1. $(x-5)^2+(y-9)^2=81$
  2. $(x-2)^2+(y-4)^2=25$
  3. $(x+4)^2+(y-7)^2=49$
  4. $(x+6)^2+(y+1)^2=16$

Graph the following circles: 

  1. $(x+3)^2+(y+2)^2=4$
  2. $(x-1)^2+(y-1)^2=9$
  3. $(x+2)^2+(y+1)^2=16$

Test to see if the following points are on the circle with equation $(x-4)^2+(y-5)^2=81$:

  1. $(13,14)$
  2. $(4,-4)$
  3. $(2,2)$
  4. $(0,5)$

Write the equations for the following circles:

  1. Graphed circle #1


     
  2. Graphed circle #2



     
  3. Graphed circle #3


     
  4. Graphed circle #3


     
  5. Graphed circle #4

Answer Key: