Ab lies in the same plane as circle p, which has a radius of 6 mm. at how many points will ab intersect circle p if pa is 7mm and pb is 3mm?

PA is longer than the radius of the circle so Point A must be outside of the circle.

PB is less than the radius of the circle so Point B must be inside the circle.

Since the ray is going from A to B it is coming inside the circle and continuing in the other direction, therefore, it must exit the circle, giving us 2 contact points

Zero is the mid point of the line segment