Algebra 2: Circles Review

Find the Center and the Radius of each circle.

1.  x2+y-42=49

2.  x+52+y-32=81

Given the following centers and radii, write the equation for the circle.

3.  Center: (-3, 2) Radius: 3

4.  Center: (-4, 0) Radius: 5

5.  Center (0,0) Radius: 8

Translate x2+y2=36

6.  3 units right, and 2 units down

7.  4 units left and 5 units up

Translate x-32+y+22=4

8.  2 units left and 2 units down

10. 5 units right and 2 units up.

Find the center and radius of each circle.

11. x2+10x+y2-6y+18=0

12. x2-4x+y2+6y-3=0

13. Write an equation of each of the following circles:

14. Find the Circumference and Area of each circle in terms of π.

15. A satellite is launched in a circular orbit around Earth at an altitude of 210 miles above the surface. The radius of Earth is 7920 miles. Write an equation for the orbit of the satellite if the center of the orbit is the center of the Earth labeled (0,0)

Find the Radius, Area and Circumference of each circle:

16. x2+y2=441

17. x-32+y2=1296

18. x2+y2+10x-8y+4=0

19. A radio station has a broadcast area in the shape of a circle with equation x2 + y2 = 8649 , where the constant represents square miles. State the radius in miles. What is the area of the region in which the broadcast from the station can be picked up?

20. The plans of a public park include a circular fountain. The outline of the fountain can be modeled with the equation x2 + y2 = 33, where the units are meters and the graph is on a grid map of the park. Find the coordinates of the center. Find the circumference of the fountain.

21. Mariah is making a graphic design on a computer using a coordinate grid. She began with a circle with center (0, 0). Then she drew a congruent circle with the equation x2 + y2 + 10x -8y +4 = 0. What was the radius of the first circle? What translation did Mariah make to draw the second circle?