x=180 - (42+73)=180- 115 x=65 ° y=180 - 131 y=49° z=x+y=65+49 z=114 ° w+49+(180-142)=180 w+49+38=180 w=180- (49+38) w=180-87 w=93° in the small triangle: the angle are t, y and ( I note the other angle) s s=180-(42+w) s=180-(42+93) s=180-135 s=45° t=180-(y+s) t=180-(49+45) t=180-94 t=86°
