Question

109° 99° x = 50° x°

Explanation:

Step1: Recall sum of interior angles of a quadrilateral

The sum of interior angles of a quadrilateral is $(4 - 2)\times180^{\circ}=360^{\circ}$.

Step2: Set up an equation

We have $109^{\circ}+99^{\circ}+50^{\circ}+x^{\circ}=360^{\circ}$.

Step3: Simplify the left - hand side

$109 + 99+50+x=258 + x$.

Step4: Solve for x

$258+x = 360$, so $x=360 - 258=102$.

Answer:

$102$