i understand normal trig + pythagorean theorem but i don't understand how to break this down into the equation.

ANSWER
[tex]21.9[/tex]EXPLANATION
We want to solve for x in the figure given.
The given triangle is an isosceles triangle, and so the perpendicular line drawn divides the line into equal halves.
This implies that we now have a right triangle as follows:
Now, we can solve for x using Pythagoras theorem:
[tex]x^2=9^2+20^2_{}[/tex]Simplify and solve for x:
[tex]\begin{gathered} x^2=81+400 \\ x^2=481 \\ x=\sqrt[]{481} \\ x=21.9 \end{gathered}[/tex]That is the value of x.