Equations of Circles in the Coordinate Plane

• Center is (5, 2) and radius is 25 units

• Center is (2, 5) and radius is 25 units

• Center is (2, 4) and radius is 5 units

• Center is (4, 2) and radius is 5 units

• Center is (-1, -3) and radius is 2 units

• Center is (1, 3) and radius is 2 units

• Center is (-1, -3) and radius is 4 units

• Center is (1, 3) and radius is 4 units

Which of the following equations represents a circle in the standard (x,y) coordinate plane with its center at (-5,6) and a radius of 3 units?

• (x - 5)² + (y - 6)² = 9

• (x - 5)² + (y + 6)² = 9

• (x+ 5)² + (y - 6)² = 9

• (x - 5)² + (y + 6)² = 3

• (x + 5)² + (y - 6)² = 3

There was an earthquake in a city. It was felt up to 80 miles from its epicenter. If the epicenter can be located at the point (15, 8) on a coordinate plane, which equation would help to find the boundary of the area that is affected by the earthquake?

• (x – 15)² + (y – 8)² = 80

• (x – 15)² + (y – 8)² = 289

• (x + 15)² + (y + 8)² = 529

• (x – 15)² + (y – 8)² = 80²

If the center of a circle is: (-4,2) and the radius is 6, what is the equation of the circle?

See Picture

• 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

Determine the equation of a circle with center (5,-3) and radius of 9

• x²+y²-10x+6y-47=4

• x²+y²-10x-6y-47=0

• 2x²+y²+10x+6y-47=0

• x²+y²-10x+6y-47=0

Answer explanation

The equation of a circle with center (5,-3) and radius of 9 is x^2 + y^2 - 10x + 6y - 47 = 0.