How can I find the size of an angle in a right-angled triangle if I know the lengths of two of the sides?

We can find any angle in a right-angled (RA) triangle if we know the lengths of two of the sides, using SohCahToa.
The first step is to identify which of the sides we know. There are three sides in a RA triangle: hypotenuse, opposite and adjacent. The hypotenuse is the longest side, and will always be opposite the RA. The adjacent is the side connected/next to the angle we are looking to find. Finally, the opposite is 'opposite' the angle. (Here I would draw a diagram showing how to identify each of these sides.)
Once we have worked this out, we can move onto to the next step: SohCahToa, which stands for:Sine(x) = Opposite/HypotenuseCosine(x) = Adjacent/HypotenuseTangent(x) = Opposite/Adjacent,where x is the angle we are trying to find.
So, for example, if we have the adjacent and hypotenuse, we know we need to use tangent to work out our angle. E.g. if the adjacent is 8 and the hypotenuse is 10, then tangent(x) = 8/10 = 0.8
Now, all we need to do is solve for x! To solve an equation, we need to get 'x' on its own. The way to do this when using sin/cos/tan is to use the inverses, which are called sin^-1, cos^-1 and tan^-1; (there's a button for each of these on your calculators. So if tan(x) = 0.8, then x = tan^-1(0.8). If we put that into our calculators, x = 38.7 (rounded to 1 decimal place).