Answer
$x = 15$
Work Step by Step
According to the triangle-angle-bisector theorem, when a ray bisects the angle of a triangle, the opposite side is divided into two segments that are proportional to the remaining two sides of the triangle.
Let's set up a proportion that compares the segments of the intersected side to the other two sides:
$\frac{12}{16} = \frac{x}{20}$
Use the cross product property to get rid of the fractions:
$16x = 20(12)$
Multiply to simplify:
$16x = 240$
Divide each side of the equation by $16$ to solve for $x$:
$x = 15$
