Standard Form of Circles

The endpoints of a diameter of a circle are (3,1) and (9,5).Find the equation of the circle?

• (x−6)²+(y−3)²=13

• (x−3)²+(y−6)²=13²

• (x−5)²+(y−9)²=13

• (x−9)²+(y−5)²=169/4

In the equation (x+2)²+(y-3)²=4, the radius of the circle is...

• 4

• 2

• 3

• 16

What is the coordinates of the centre and the radius of the circle with equation:
(x - 4)^2 + (y - 3)^2 = 25^ ?

• Centre  (4,3)
  Radius = 5 units

• Centre  (4,3)
  Radius = 25 units

• Centre  (-4,-3)
  Radius = 25 units

• Centre  (-4,-3)
  Radius = 5 units

Which equation matches the circle on the graph?

• (x-3)²+(y-4)²=16

• (x-5)²+(y-2)²=20

• (x+3)²+(y+4)²=16

• (x-9)²+(y-16)²=32

A circle has the equation x² + y² - 12x + 8y + 3 = 0. Write the equation in standard form.

• (x - 6)² + (y + 4)² = 49

• (x + 4)² + (y - 6)² = 49

• (x - 6)² + (y + 4)² = 55

• x² + y² = 55

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

Convert the equation of the circle from general to standard form.

• A

• B

• C

• D

Find the center and radius of the circle: x² + y² + 14x - 2y = -1.

• center = (-7, 2) radius = 3

• center = (-7, 1) radius = 7

• center = (-4, 1) radius = 7

• center = (-4, 2) radius = 3

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