Question

How do you write an equation of a circle with center at (5,10), r=7?

Answer 1

`(x-5)^2 + (y-10)^2 = 49`

Explanation:

Standard equation of a circle: `(x-h)^2 + (y-k)^2 = r^2`, where `"center": (h, k), r = "radius"`

`r = 7`, so `r^2 = 7^2 = 49`
`h = 5, k = 10`

So: `(x-5)^2 + (y-10)^2 = 49`