Answer:
Step-by-step explanation:
First set up an equasion
180 (angles added together) = x+20 + 210-3x + x
then simplify
180 = 230 + x + x -3x
180 = 230 - x
then subtract 230
180 - 230 = -50 = -x
divide -1 from the x
50 = x
check
50 + (50 + 20) + (210 - (3*50)) = 180
