You use the law of cosines whenever you're given a SAS triangle. The formula is
C is the given angle, c is the side opposite this angle, and a/b are the given sides adjacent to angle C.
In this case, if is the length of the missing side, then
Answer:
product of 12 and a number, 12 groups of a number, a number multiplied by 12
Answer:
-15 plus or minus the square root of 65 all over 4 (All over means fraction)