The mid-points of two sides of a triangle are joined by a straight line. What is true of that line?

1. The mid-point theorem describes exactly this construction inside a triangle. 2. It states that the joining line is parallel to the third side of the triangle. 3. It also states that the joining line is equal to half the length of that third side. 4. So the line is both parallel to the third side and half as long as it. 5. Making it equal in length would leave no room for the triangle to close, which rules that option out. 6. Being at right angles contradicts the parallel part of the theorem, which is the trap in the last option. _Source: Siyavula Mathematics Grade 10 (Everything Maths, CC BY 4.0), Chapter 12: Euclidean geometry_