Part V. Two-Column Proof (16 points)

18. “Artistic shading” is optional.

(a) In the space below, draw horizontal plane m and vertical plane n, intersecting along , where M is the midpoint of horizontal segment lying in plane m. Mark point T lying in plane n such that . You may raise your hand if you would like Mr. Hansen to approve your diagram, but no hints will be provided. Please break the task down into six small pieces:

    1. Horizontal plane, vertical plane
    2. Label m and n to match instructions
    3. Line of intersection
    4. Point C at some random location on line of intersection
    5. Point M at midpoint of , where lies in m
    6. Point T (lying in n) such that

















(a) Fill in the blank: ABT is a plane figure because ____________________________ .

(b) Given: Planes m and n
lies in m
                 M is midpoint of

                 T lies in n

     Prove: TA = TB

Provide a full 2-column proof on the back side of this page. (This is a rather short proof after you have listed the givens.) You do not need to draw the diagram a second time.