#1**+1 **

one last time any one help in the next 8 minutes and i will not ask another question today and sorry i forgot the image

travisio Aug 5, 2019

#3**0 **

"Coplanar" means, that points are situated in one plane.

If you have a flat surface, like a soccer-field, and you mark random points on this soccer-field, the points will all be coplanar.

Anything that is above or below the soccer-field is not colplanar with the points that are on the soccer-field.

The picture you present shows the points A, B and R to be colinear. That means, they are all connected by a straight line. As they are connected by a straight line, they don't span up a plane. Thus they can't be coplanar, because you need any combination of the points A, B oder R and another point outside the line AB. Depending on which point other than A, B or R you choose, you will have a plane. All three points, A, B and R will be coplanar with that plane.

Trotzdem Aug 12, 2019