Answer
$x\approx 8.39$
Work Step by Step
First, one should find the length of the short leg of the biggest triangle (the one with the 28º angle). To do so, one should use the tangent function. The variable $a$ will be used to represent that leg:
tan$(28º)=\frac{a}{50}$
$a=$tan$(28º) \cdot 50\approx 26.59$
Now, one should do the same with the smaller triangle. The variable $b$ will be used to represent the short leg:
tan$(20º)=\frac{b}{50}$
$b=$tan$(20º) \cdot 50\approx 18.20$
$x$ will be the subtraction of $b$ from $a$:
$x\approx26.59-18.20\approx 8.39$
