Question

What is X? How do you know?

Answer 1

The sides of a right triangle are related by trig functions of the acute angles. The relationships are described by the mnemonic SOH CAH TOA. The meaning of this is
.. Sin = Opposite/Hypotenuse
.. Cos = Adjacent/Hypotenuse
.. Tan = Opposite/Adjacent

Here, you are given the adjacent side and the hypotenuse for the angle. This means you can use the relation
.. Cos = Adjacent/Hypotenuse

Putting in the given information lets you find x.
.. cos(22°) = x/11
.. 11*cos(22°) = x ≈ 10.199