Law of Cosines

If three sides of a triangle are given, the Law of ____ is used to solve the triangle.

• Cosines
• Sines
• Tangent
• Cosecents

Which law would you use?

• Law of Sines

• Law of Cosines

Which law would you use?

• Law of Sines

• Law of Cosines

Find XZ

• 16.004 meters
• 544.165 meters
• 34.7 meters
• 1204.165 meters

Find angle Z

• 20.15°

• 71.23°

• 51.06°

• 57.71°

Find QR

• 34.7 km
• 2.2 km
• 13.74
• 31.1 km

Use Law of Cosines to find angle T

• 62.2°

• 53.1°

• 59.5°

• 64.7°

8.Solve for x

• 3.85

• 4.25

• 3.35

• 5.65

Given the triangle: A=50°, b=5, c=2. Find missing length side a

• 3.12
• 4.02
• 14.12
• 28.24

Solve the Triangle

a=38, b= 31, c= 35

Find <A, <B and <C

Hint: First find one missing angle (you choose), then use that new information to find a second angle. You will need both the law of sines and cosines.

• A= 43°, B= 47°, C= 90°

• A= 70°, B= 50.1°, C= 59.9°

• A= 50.1°, B= 70°, C= 59.9°

• A= 60°, B= 70°, C= 50°