This week in Math 10, I have chosen to talk about finding missing angles of a triangle using trigonometry. Please refer to my last blog post for the underlying concepts.

In this example, (angle theta) is an unknown value in degrees. We know that the adjacent side is 8cm, and the hypotenuse 24cm. That would mean that the cosine of the triangle is the following:

Now, all math can be reversed. 2+2=4, and 4-2=2. Sines, cosines and tangents are no exception. To do this, we do an inverse cosine.

Now, operations involving sines, cosines or tangents are very difficult. For the most part, you will be using a scientific calculator and its buttons for the respective functions. In this case, , which may be a shift option for another button on some calculators. You will also have to input the brackets and the fraction, the latter being added by a button that typically looks like , potentially with a and b being replaced by empty squares.

Now, solving the previously written equation, we get the following:

For the most part, you will want to round up the resulting number to the next degree (whole number.)

We now know that is roughly equivalent to