A right-angled triangle has an angle of 30 degrees and its hypotenuse has a length of 9cm. Find the length of either of the triangle's other two sides.

Please note that this solution is easier to explain with 2 diagrams 

The side opposite of the 30 degree angle: 

If we have the hypotenuse and require the length of the opposite side then we would use sin (SohCahToa).

Therefore, sin30 = opposite/9

9sin30 = opposite length 

4.5cm = opposite length 

The adjacent side: 

We have the length of the hypotenuse and need to find the adjacent side then we use Cos (SohCahToa)

Therefore, cos30 = adjacent/9

9cos30 = adjacent 

7.80cm (2d.p) = adjacent length.