Answer: x= 15
Step-by-step explanation: So to prove these two lines A and B are congruent the angles must line up which mean rules of complimentary, Supplementary and alternating angles apply. For angles 2 and 4 due to our alternating angles rule they add up to equal 180 so in math
2x+10+4x+80 = 180 or 6x+90=180 where x = 15