1. in this diagram, how many points are coplanar with points a, b and r? 2. how many labeled points are between points b and u?

1. Two points are coplanar if they are located on the flat surface. In this case, points A, B and R are co-planar with point C.

2. It depends on the situation. If you are finding for co-planar points between B and U, there would only be one: point T. Now, if it does not specify which plane, there are three: points R, T and E.

Do the inverse operation