Question 169628
lets each angle x,y,and z.   1st,2nd,and 3rd angles respectively
:
x+y+z=180...eq 1
x=y-20......eq 2
z=2y........eq 3
:
take the value of x in eq 2 and the value of z in eq 3 and plug them into eq 1
:
(y-20)+y+(2y)=180
:
4y=200
:
{{{highlight(y=50)}}}degrees...2nd angle
using eq 2{{{x=50-20=30)}}}degrees..1st angle
using eq 3{{{z=2(50)=100)}}}degrees...3rd angle