Law of Cosines Word Problems

Would you use the Law of Sines

or the Law of Cosines?

• Law of Sines

• Law of Cosines

Find the missing side.

• 15.9 in.

• 22.8 in.

• 19.2 in.

• 521.1 in.

Which law would you use?

• Law of Sines

• Law of Cosines

What is the distance across the river? The two sides are 4.15 miles and 5.33 miles. The included angle measure is 37 degrees.

• 2.9 miles

• 3.2 miles

• 3.6 miles

• 3.9 miles

Find QR

• 34.7 km

• 2.2 km

• 13.74

• 31.1 km

Which Law would you use to solve for Angle B?

• Law of the Jungle

• Law of Cosines

• Law of the Gravity

• Law of Sines

Find AB

Farmer Chuck Norris needs to enclose a triangular field along a river. One side of fencing is already in place, and Farmer Chuck has 40 feet of fence for the open side. How far away from point A (along the river) can Farmer Chuck put the fence?

• 23.4 feet

• 85.3 feet

• 39.3 feet

• 51.3 feet

The diagram shows a lake. Which formula would you use to determine the distance across the lake?

• Law of Sines

• Law of Cosines