Question

Is the point P (2,8) on the inside or outside of the circle described with equation x^2+y^2=100?

Answer 1

Points
`(x,y)` on the circle satisfy
`x^2+y^2=100`.

Points inside the circle satisfy
`x^2+y^2<100`.

Points outside the circle satisfy
`x^2+y^2>100`.

We have

`2^2+8^2=4+64=68<100`

so the point (2, 8) lies inside the circle.