If you are working with a triangle that has a right angle somewhere, you can easily determine the tangent angle as long as you know the length of two sides of the triangle.

In Microsoft Excel this is even easier, because you can use built-in functions for this.

A tangent angle is an angle in a triangle for which you know the length of the side opposite the angle and the side next to it.

For example, imagine your boss tells you to adjust a ladder to exactly 70 degrees from the ground. Unless you have special tools, it would be difficult to measure whether the angle between the ladder and the ground is exactly 70 degrees.