Circle Quiz Review

Match each equation to its description.

• Circle centered at (1, -4) and radius √3

• (x – 1)² + y² = 9

• Circle centered at (1, -4) and radius 3

• (x – 1)² + (y + 4)² = 3

• Circle centered at (1, 4) and radius √3

• (x – 1)² + (y – 4)² = 3

• Circle centered at (1, 0) and radius 3

• (x – 1)² + (y + 4)² = 9

• Circle centered at (0, -4) and radius 3

• x² + (y + 4)² = 9

Which graph corresponds to

(x+2)²+ (y-3)²=36

• A

• B

• C

• D

What is the equation for this circle?

• (x+1)+(y+1)=9
• x²+y²=9
• x+y=9

Mathematical Equivalence

ON

Determine the equation of the circle in standard form:
x² + y² + 4x + 6y - 36 = 0

• (x+2)² + (y+3)² = 49
• (x+2)² + (y+3)² = 13
• (x-2)² + (y-3)² = 49
• (x-2)² + (y-3)² = 13

Complete the Square:

x² + 14x + (a)  

Find the center of the circle if the endpoints of a diameter of the circle are at (-12, -7) and (3, 5)

• (-9/2, -1)

• (-15/2, -6)

• (9/2, 1)

• (15/2, 6)

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

Determine the center and radius:
x² + y² - 10x + 8y -8 = 0

• C = (5,-4) r = 7
• C = (-5,4) r = 7
• C = (-4,5) r = 49
• C = (5,-4) r = 49