Problem:
Mathematics - Proof of Midpoint Theorem using Vectors
The midpoint of a side of a triangle in R^3 is the point that bisects that side (i.e., that divides it into two equal pieces). Let triangle in R^3 have sides A,B and C and let denote L denote the line segment between the midpoints of A and B. Prove that L is parallel to C and that the length of L is one-half the length of C.