The sum S of the interior angle measures of a polygon with n sides is equal to the product of (n-2) and 180^(∘).
S=(n-2) 180^(∘)
The given polygon has 4 sides. We can substitute this number for n in the formula to find the sum of the measures of the interior angles of the polygon.
The sum of the angle measures of the given polygon is 360^(∘). Next, we can write an equation that sets S equal to the sum of the angle measures.
S= Sum of the angle measures
⇓
360^(∘)= 60^(∘)+ 128^(∘)+ 95^(∘)+ x^(∘)
Finally, we can solve this equation for x. For simplicity, we will remove the degree symbol while solving.
