Question

What is the radius of a circle given by the equation `(x+1)^2+(y-2)^2=64`?

Answer 1

The radius of this circle is `8` (units).

Explanation:

The equation of a circle is:

`(x-a)^2+(y-b)^2=r^2`, where `r` is the radius, and `P=(a,b)` is the circle's centre, so the given circle has:

• Radius of `sqrt(64)=8` (units)
• Centre at `P=(-1;2)`