There is 180 degrees in a triangle. What you need to do is set up an equation and solve for x.
(7x + 10)+(x+20)+2x =180
Combine like terms:
10x + 30 = 180
Solve for x:
10x= 150; the largest angle
X=15
Plug x into the equations
7(15)+10= 115
(15) + 20 = 35
2(15)=30
Just to check your work:
115+30+35=180
