Given a trigonometric ratio, calculating angle sizes involves using the ‘inverse’ function. In other words, when you are given a trigonometric ratio for an angle, we can determine the size of the angle by using the ‘inverse’ function.
Let’s look at some examples calculating angle sizes-
Example 1 : Given tan θ =
= 23.19859 or 23° 11′ 54.9″
θ = 23° 12′ (to the nearest minute)
Example 2 : Given sin θ = 0.5
θ = (0.5)
Example 3 : Given cos θ=
Tip for scientific calculator:
Given cos θ = ;
When using a scientific calculator to solve the above equation, use the following keys in this order:
Shift or 2nd followed by cos = 28.07249 or 28° 4′, and finally DMS key.
Here’s how to do angle measurement