Answer:
The value of x measures 20°
Step-by-step explanation:
Given that we have an isosceles triangle (two sides of equal length), we know that the two interior angles at the base adjacent to each equivalent side must also be equivalent.
The line extension from the triangle reveals an exterior angle that will be supplementary to the interior (they will add up together to make 180°)
Knowing this, we can solve for x.
180 = (5x + 13) + (3x + 7) Combine like terms
180 = 8x + 20 Take 20 away from both sides
160 = 8x Divide both sides by 8 to isolate x
20 = x
Therefore the value of x measures 20°
