Vertical Angles Theorem: If two lines ing intersect, then vertical angles are congruent. 3. Discuss with your partner the pictorial proof of the The vertical angles are vertical angles theorem below. Complete the description for each picture shown in the pictorial proof. and Picture Description The yellow angle and the red angle are being added. and A pictorial proof of the vertical angles theorem is shown. Therefore, In the same manner, Proofs play an important role in the course of geometry. Proofs can take on many forms. They are the set of logical steps that explain why something is true. When programmers write a new game, they use a set of logical steps. When you tie your shoes, you use a set of logical steps. Unit 2: Proofs and Logic