Law of Sines & Law of Cosines

What is the Law of Cosines?

• SinA/a=sinB/b=sinC/c

• $a^2=b+c-2a^2b^2CosA$
  

• $b^2=a^2+c^2-2acCosB$

• $c^2=a^2+b^2-2abCosA$

Sam is building a swing set for his daughter . The two legs of the swing set will be 10 feet long. They will be joined at a 45 degree angle. How far apart will the legs be (to nearest 100th) ?

• 6.54

• 7.65

• 4.32

• 7.75

Which would you use to solve the following triangle? Angle A=30, Angle C=100 , b= 2

• Heron's Formula

• Law of Cosines

• Law of Exponents

• Law of Sines

Solve for angle A to nearest degree

a=1, b= 2, c=2

• 29 degrees

• 33 degrees

• 44 degrees

• 28 degrees

Solve for angle C to nearest degree.

Angle A = 77, a=20, c=15

• 46 degrees

• 50 degrees

• 47 degrees

• 41 degrees

Under which circumstances will you use the Law of Cosines?

• SSS, AAS

• AAS, SAS

• SSS, SAS

• ASA, SAS

Solve for side a to nearest 100th.

Angle A= 88 degrees, b= 8, c= 2

• 8.34

• 8.18

• 9.12

• 7.47

Find side a to nearest hundredth

Angle A= 48, c=10, b=12

• 9.14

• 9.17

• 8.26

• 9.13

Under which circumstances can you use the Law of Sines?

• SSS, AAS

• AAS, SSA

• SAS, SSA

• SSS, ASA

What is the area of the following triangle to the nearest tenth?

Angle C 43, b=10, c=8

• 29.4

• 27.3

• 27.0

• 31.2