From SOH CAH TOA, we see that we need to use the cosine ... The '12' is dividing on the right hand side, so when it moves to the other side it does the opposite, therefore it will multiply.

As the numbers are known on the opposite and the hypotenuse, then we look for the ratio which uses both these sides (SOH CAH TOA). That ratio is the sine ratio. \(\sin (x^\circ ) = \frac{{opposite}}{{ ...