Verified answer

x + x/3 = 80

3x + x = 240

4x = 240

x = 60º

pronto

x+x/3=80

3x+x=240

4x=240

x=240/4

x=60º

.

x+x/3=80

2x=80.3

2x=240

x=240/2

x=120