Answer :
the angle measures would have to add up to 180 as a general rule so make x the multiplier and:
4x+5x+6x=180
15x=180
x=12
so then
4(12)=5(12)+6(12)=180
48, 60, and 72
4x+5x+6x=180
15x=180
x=12
so then
4(12)=5(12)+6(12)=180
48, 60, and 72