Equation of Circle Review

What is the equation of the circle given the diameter with endpoints (1, 2) and (3, -2)? (Hint: Use midpoint and distance formula)

• (x+2)²+y²=5

• (x+1)²+(y+2)²=5

• (x-2)²+y²=20

• (x-2)²+y²=5

What is the general form of the circle (x+4)²+(y-2)²=12?

• x²+y²+8x-4y+8=0

• x²+y²+8x-4y+20=0

• x²+y²+8x+4y+8=0

• x²+y²+8x-4y= -8

Which circle represents the equation
x²+y²-12y+27=0? (Hint: convert to standard form)

• A

• B

• C

• D

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 equation of the circle shown in the graph?

Mathematical Equivalence

ON

Center is at (-3, 1) and radius is 3.

• (x + 3)² + (y - 1)² = 9

• (x - 3)² + (y + 1)² = 9

• (x - 3)² + (y + 1)² = 3

• (x + 3)² + (y - 1)² = 3

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

• (x + 3)² + (y - 1)² = 9
• (x - 3)² + (y + 1)² = 9
• (x - 3)² + (y + 1)² = 3
• (x + 3)² + (y - 1)² = 3

Which of the following points is outside of the circle (x+5)²+(y-4)²=30

• (-2, 6)

• (5, 4)

• (-6, -1)

• (0, 2)

What is the center of the circle x²+y²-15=8x -14y? (Hint: Move all terms so the equation is in general form, then complete the square to convert to standard form.)

• (4, -7)

• (-4, 7)

• (8, -14)

• (-8, 14)