Explanation:
The formula for law of cosines is:
[tex]a^{2} = b^{2} + c^{2} - 2bc(cosA)[/tex]
This is written at the top of your paper.
The angle is substituted where the capital A is. The side opposite to the angle is the angle name's lowercase. The two other sides are b and c.
Substitute all the information you know, then isolate the variable that you do not know.
When your formula is rearranged to look like this:
[tex]\frac{a^{2} - b^{2} - c^{2}}{- 2bc} = (cosA)[/tex]
Solve the left side and punch into your calculator:
cos⁻¹(left side) to find the angle A.
