Question

How do you find the radius of a circle with equation `(x-2)^2+(y-2)^2=r^2` that contains the point at (2,5)?

Answer 1

`3`.

Explanation:

If the circle `(x-2)^2+(y-2)^2=r^2` passes through the

point `(2,5)`, the co-ords. of `(2,5)` must satisfy the given eqn.

`:. (2-2)^2+(5-2)^2=r^2=9`, giving, `r=3`.

But, in the given eqn. of circle, `r` denotes the radius.

Therefore, the radius of the circle in question is `3`.