Law of Cosines Quick Check

Which of the following formulas shows the Law of Cosines?

• c² = a² + b² - 4ac + cosA

• c² = a² - b² - 2abcosC

• c² = a² + b² - 2abcosC

• (cos A)/a = (cos B)/b

Find angle Z

• 20.15°

• 71.23°

• 51.06°

• 57.71°

Use Law of Cosines to find angle T

• 62.2°

• 53.1°

• 59.5°

• 64.7°

Find XZ

• 16.004 meters

• 544.165 meters

• 34.7 meters

• 1204.165 meters

Find the missing side.

• 15.9 in.

• 22.8 in.

• 19.2 in.

• 521.1 in.