Circles

What is the standard equation of a circle with center (h, k) and radius r?

• (x - h)² + (y - k)² = r²

• (x + h)² + (y + k)² = r²

• (x - h)² + (y - k)² = 2r

• (x - h)² + (y - k) = r²

What is the center and radius of the circle given by the equation (x - 1)² + (y + 2)² = 25?

• C(1, -2), r=5

• C(0, 0), r=5

• C(1, -2), r=10

• C(-1, 2), r=5

Write the equation of a circle with center (2, 3) and diameter 10.

• (x - 2)² + (y - 3)² = 25

• (x + 2)² + (y - 3)² = 25

• (x - 2)² + (y + 3)² = 25

• (x - 2)² + (y - 3)² = 100

What is the center of the circle given by the equation (x - 3)² + (y + 5)² = 36?

• C(3, -5)

• C(3, 5)

• C(-3, -5)

• C(-3, 5)

Write the equation of a circle with center (4, -8) and radius 5.

• (x - 4)² + (y + 8)² = 25

• (x + 4)² + (y - 8)² = 20

• (x - 4)² + (y - 8)² = 25

• (x + 4)² + (y + 8)² = 30

What is the diameter of a circle with radius 5?

• 5

• 10

• 15

• 20

What is the diameter of a circle with radius 10?

• 15

• 20

• 25

• 30

What is the radius of the circle given by the equation (x + 2)² + (y - 4)² = 49?

• 5

• 6

• 7

• 8

What is the equation of a circle with center (0, 0) and radius 1?

• x² + y² = 1

• (x - 1)² + (y - 1)² = 1

• x² + (y + 1)² = 1

• (x + 1)² + y² = 1

What is the center and radius of the circle given by the equation (x + 4)² + (y - 2)² = 64?

• C(-4, 2), r=8

• C(4, -2), r=8

• C(-4, 2), r=6

• C(0, 0), r=8