Calculating unknown side length
Step 1:
Label the sides of the triangle based on where the cosine is
Step 2:
Work out what angles you have e.g.. sine, cosine, or tan
Step 3:
Substitute the side lengths
Step 4:
Once it is substituted, get the pro numeral by itself
Step 5:
Use your calculator to find the final answer. e.g... if it was Sine, put sine in to the calculator first and then the sum