Law of Cosines and Heron's Formula

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 the area of the triangle

• 24.0 cm²

• 47.9 cm²

• 19.7 cm²

• 23.967 cm²

Find angle A

• 53.6

• 13.3

• 113.1

Calculate the length of BC

• 24

• 20

• 27

• 23

Use the Law of Cosines to find the value of x.  (Level 1)

• 41.7

• 51.7

• 61.7

• 71.7

Use Law of Cosines to find angle T

• 62.2 degrees

• 53.1 degrees

• 59.5 degrees

• 64.7 degrees

Using Heron's Formula, find the Area. #39

• 56

• 28

• 24.2

• 104.4

Using Heron's Formula, find the Area.

• 56

• 28

• 24.2

• 104.4

Using Heron's Formula, find the Area.

• 35

• 49

• 28.9

• 27.8

Use Heron's Formula to find the Area.

• 76.1 yd²

• 90 yd²

• 99.8 yd²

• 79.8 yd²