Let's focus out attention on the triangle:
Since the yellow triangle and the white triangle in the image are similar, we can say that
[tex]\angle BCA=10[/tex]Since we're focusing on a right triangle, we can use the trigonometric formula
[tex]\tan (\alpha)=\frac{opposite\text{ side}}{\text{adjacent}}[/tex]In this case
[tex]\tan (10)=\frac{x}{500}[/tex][tex]\tan (10)\approx0.1763[/tex][tex]0.1763\cdot500=x[/tex][tex]x=88.16[/tex]Round to the nearest tenth
[tex]x=88.2[/tex]