lesha wants to prove that the measures of the 3 angles in a triangle always have a sum of 180 She decided to prove this conjecture using rigid motion She began with triangle ABC shown in Figure 1 B 16 Figure 1 C Figure 2 Rotate triangle ABC degrees on the midpoint of Rotate triangle ABC degrees on the midpoint of ince we used 2 rigid motions and all three angles form a straight line and a straight line equals angles will equal 180 degrees we can show that all