Answer:
7.9
Step-by-step explanation:
The mnemonic SOH CAH TOA reminds you of the relationship of the hypotenuse and the side opposite an angle:
... Sin = Opposite/Hypotenuse
For your geometry, this is ...
... sin(21°) = x/22
Multiplying by 22 gives ...
... x = 22·sin(21°) ≈ 7.9
