
Mason G. answered 10/31/19
Knowledgeable Private Math Tutor with private school experience
We know that all the angles of a triangle sum to 180 degrees.
Angle 1 = is unknown, so lets label it "x"
Angle 2 = x+6
Angle 3 = 8x-6
So, Angle 1 + Angle 2 + Angle 3 = 180 ->Substitute Values
(x) + (x+6) + (8x-6) = 180 -> Combine like terms
10x = 180 -> Divide by 10
x = 18
Substitute the value of x back into the Angle measures
Angle 1 = 18
Angle 2 = 18 + 6 = 24
Angle 3 = 8(18) - 6 = 144-6 = 138
Check yourself by adding all the angles together
18+24+138 = 180!