How to determine the angle of a right triangle from the length of two sides

To determine the angle of a right triangle, you need to figure out first which trigonometric function is required. You can tell which one is needed based on where is the angle you need to solve and where are the sides that you know how long they are. Once you know which function you need, you can use that function with the "-1" on it. Use those trigonometric functions by dividing those sides following the order of those ratios. The screenshot below will help you understand the given task better. I was giving the explanation as clear as I can. For the example below, you need use the tangent ratio. Here's the equation: Tan-1(5/2). You could also use Tan-1(2.5) and still get the same answer.