Law of Sines, Law of Cosines and Area

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

Which Law would you use?

• Law of Sines
• Law of Cosines
• Law of the Jungle
• Law of Gravity

Which Law would you use?

• Law of Sines
• Law of Cosines
• Law of the Jungle
• Law of Gravity

Amanda and Jamie are standing 25 feet apart and spot a bird in the sky between them. The angle of elevation from Amanda to the bird is 55 degrees, and from Jamie to the bird is 63 degrees. How far away, to 2 decimal places, is the bird from Amanda?

• 25.23 ft

• 23.19 ft

• 22.15 ft

• 20.85 ft

• A

• B

• C

• D

What is the area of this triangle to three decimal places?

• 14.494 meters squared

• 108.184 meters squared

• 54.092 meters squared

• 54.350 meters squared

Find m<B to the nearest whole number.

• A

• B

• C

• D

Find the length of Side BC.

• 33

• 24

• 12

• 29

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

• 41.7
• 51.7
• 61.7
• 71.7

The sides of a triangle are 15 cm, 17 cm and 8 cm. What is its area?