Use the Law of Cosines to find the measure of ∠A. Round to the nearest degree. a = 12, b = 5, c = 9

Use: a² = b² + c² – 2bc cos A

When rates are expressed as a quantity of 1, such as 2 feet per second or 5 miles per hour, they are called unit rates. if you have a multiple-unit rate such as 120 students for every 3 buses, and want to find the single-unit rate, write a ratio equal to the multiple-unit rate with 1 as the second term.