Question

What is the circumference of the circle whose equation is `(x-9)^2+(y-3)^2=64`?

Answer 1

The circumference of circle `(x-9)^2+(y-3)^2=64` is `16pi`.

Explanation:

Equation of a circle with center `(h,k)` and radius `r` is

`(x-h)^2+(y-k)^2=r^2`

Hence `(x-9)^2+(y-3)^2=64=8^2` is a circle

with center `(9,3)` and radius `8`

As circumference of circle of radius `r` is `2pir`

the circumference of circle `(x-9)^2+(y-3)^2=64` is `2xxpixx8=16pi`