Tangent Plane from a Point to a Sphere

Tangent Plane from a Point to a Sphere

For a sphere with centre $$c$$ and radius $$r$$, tangent planes from an external point $$p$$ touch the sphere at points $$t$$ satisfying:

$$CT\perp PT$$

and:

$$PT^2=PC^2-r^2$$

Usage

- Used in problems involving tangent planes drawn from an external point.