Question

How do you find the equation of the circle with center at (-2,5) and radius of 5?

Answer 1

`(x + 2)^2 + (y - 5)^2 = 5^2`

Explanation:

General formula for a circle; `(x + a)^2 + (y + b)^2 = r^2`
Notice how r is the radius. So if you had 25 on that side the radius would be `sqrt25 = 5`.
For the origin think opposites! Notice how the x co-ordinate of the origin is paired with x and the y co-ordinate with y. However, the signs are reversed.