Solution
We have the following equation given:
m<3 + m<4 = m <1
the reason why this equation must be true is the following:
D. m<1 + m<2 = 180º and
m<3 +m<4 + m<2 = 180
Since <1 and <2 are supplementary
And the sum of the angles a triangle needs to be 180º
