An outside angle is equal to the sum of the two opposite inside angles.
This means 150 = x + (x+20)
Now solve for X:
150 = x + x+20
simplify:
150 = 2x+20
Subtract 20 from each side:
130 = 2x
Divide both sides by 2:
x = 130/2
x = 65
Now we have X = 65
Solve for the other angle with x in it, by replacing x with 65:
x = 20 = 65 +20 = 85
The three inside angles of a triangle need to equal 180 so now we can solve for Z:
z = 180 - 65 - 85 = 30 degrees.
X = 65, Z = 30
