Sagot :
Answer:
base angles = 20° each;
vertex angle = 140°
Step-by-step explanation:
let: x be the vertex angle
y be the base angles
sum of angles of a triangle in 180°
x+y+y=180
x+2y=180, this is your eq. 1
The measure of one of the base angles is 1/6 times the difference of the vertex angle and one of its base angles, so
y=(x-y)/6
[y=(x-y)/6]*6
6y=x-y
x-y-6y=0
x-7y=0
x=7y, substitute this to eq. 1
x+2y=180
7y+2y=180
9y=180
y=20
x+2y=180
x+2(20)=180
x-40=180
x=140