Equation of Circle Review

The equation of a circle is x² + y² + 6x - 12y + 20 = 0. Write the equation in standard form.

• (x - 3)² + (y + 6)² = 25

• (x + 3)² + (y - 6)² = 25

• (x - 3)² + (y + 6)² = 45

• (x + 3)² + (y - 6)² = 5

A circle has the equation x² + y² + 10x - 4y + 20 = 0. Write it in standard form.

• (x - 5)² + (y + 2)² = 9

• (x + 5)² + (y - 2)² = 3

• (x + 5)² + (y - 2)² = 9

• (x - 5)² + (y + 2)² = 3

Select the matching graph.

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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

Which of the following equations of circles in standard form with center at (-3, 4) and a radius of 5 units?

• x² - y² = 25

• x² + y² = 25

• (x - 3)² + (y + 4)² = 25

• (x + 3)² + (y - 4)² = 25

Select the equation of a circle that has a diameter of 12.

• (x-6)²+(y+6)²=12

• (x-12)²+(y-2)²=6

• (x+1)²+(y-12)²=144

• (x-4)²+(y-1)²=36

Which of the following equations of circles in standard form with center at (-5, -8) and a radius of 6 units?

• (x - 5)² - (y - 8)² = 36

• (x + 5)² - (y + 8)² = 36

• (x + 5)² - (y + 8)² = 36

• (x + 5)² + (y + 8)² = 36

Select all equations that have a radius of 3.

• (x-3)²+(y-3)²=3

• (x+6)²+(y-2)²=9

• (x+5)²+y²=6

• (x-7)²+(y-1)²=9

• (x-2)²+(y-3)²=6

Which of the following equations of circle in general form given the center at (0, 0) and radius of 3 units?

• x² - y² = 9

• x² + y² = 9

• x² + y² - 9 = 0

• x² + y² + 9 = 0

What is the center and the radius of x² + y² = 9?

• (0, 0); r = 81units

• (0, 0); r = 9 units

• (0, 0); r = 3 units

• (0, 0); r = -3 units