STEP 1: Identify and Set Up
We have a trapezoid divided by a straight line that divides it assymetrically. We know from the all too famous geometric rule that adjacent angles in a trapezoid are supplementary. Mathematically, we can express thus:
Hence, from this relation, we can find our unknown angles.
STEP 2: Execute
For <1
<1 = 60 degrees
For <2 & <3
We know from basic geometry that a transversal across two parallel lines gives a pair of alternate angles and as such, <1 = <3 = 60 degrees
We employ our first equation to solve for <2 as seen below:
Therefore, <1 = <3 = 60 degrees and <2 = 20