Respuesta :

3x+x+20 = 180
4x = 180-20
4x = 160
x = 40

×+20+3x+2x+38+C=360
40+20+3×40+2×40+38+C=360
40+20+120+80+38+C=360
298+C=360
C=360-298
C =62°