The lines on the different sides show you which sides are congruent to the other. For example the one with one like is equal to the other side with one line on the other side. The one with two lines is equal to the other one with two lines and the one with three lines is also equal to the other with three lines. In order to prove they are congruent, you can prove the one with 1 line is congruent because it faces directly across from it's counterpart. The other two are the same because they are on the same line when they meet with the other
