12.5 Equations of Circles

Write the equation of a circle with center (7, 0) with radius 3.

• (x - 7)² + y² = 9

• x² + (y -7)² = 9

• (x - 7)² + y² = 3

• x² + (y -7)² = 3

What are the coordinates of the center and the radius of the circle with equation:

(x - 4)² + (y - 3)² = 25 ?

• Center (4,3)

  Radius = 5 units

• Center (4,3)

  Radius = 25 units

• Center (-4,-3)

  Radius = 25 units

• Center (-4,-3)

  Radius = 5 units

What is the equation of the circle?

• (x+1)² + (y +1)² = 3

• (x+1)² + (y -1)² = 3

• (x+1)² + (y +1)² = 9

• (x-1)² + (y -1)² = 9

What is the center of the circle with this equation is (x+2)²+(y-4)²=41?

• (-2,41)

• (-2,4)

• (2,-4)

• (2,41)

What is the radius of the circle

(x+7)²+(y-2)²=144?

• 7

• 12

• 24

• 144

What is the equation for this circle?

• (x+1)²+(y+1)²=9

• x²+y²=9

• x²+y²=6

• x²+y²=3

The diameter of a circle has length 12. The center is at (-5, 2). Give the equation of the circle.

• (x - 2)² + (y + 5)² = 36

• (x - 5)² + (y + 2)² = 6

• (x + 5)² + (y - 2)² = 36

• (x + 2)² + (y - 5)² = 6

In the circle represented by the equation (x-4)²+(y-3)²=25, the diameter is

• 10

• 3

• 5

• 25

In the equation (x-3)²+(y+4)²=121, the radius of the circle is

• 242

• 11

• 121

• 22

See Picture

• A

• B

• C