Equation Of A Circle
(x - a)^{2} + (y - b)^{2} = r^{2}
where
a is the x co-ordinate of the centre of the circle
b is the y co-ordinate of the centre of the circle
r is the radius of the circle

In terms of showing method and avoiding error
especially with
directed numbers the following format can be very useful
[x - (a)]^{2} + [y - (b)]^{2} = (r)^{2}

Example

(x + 2)^{2} + (y - 3)^{2} = 5^{2}

[x + 2]^{2} + [y - 3]^{2} = 5^{2}

[x - (-2)]^{2} + [y - (3)]^{2} = (5)^{2}

a = (-2)

-2 is the x co-ordinate of the centre of the circle

b = (3)

3 is the y co-ordinate of the centre of the circle

r = (5)

5 is the radius of the circle

Equation of a circle where the center of the circle is at the origin (0,0)

Equation of a circle where the center of the circle is not at the origin

Writing the equation of a circle when given the center and radius

SEARCH
Equation Of A Circle
Equation Of A Circle Worksheets