Using the law of cosines for a triangle with SAS

The video tutorial explains how to solve a triangle using the law of cosines and the law of sines. Initially, the law of cosines is applied to find the length of side A. Then, the law of sines is used to determine the angles of the triangle, specifically focusing on angle C. The tutorial also discusses the verification of possible cases for angle C and concludes with calculating angle B using the angle sum theorem.

Why can't the law of sines be applied initially in the problem?

• Because the triangle is not right-angled

• Because there is no known ratio

• Because there is no known side

• Because there is no known angle

What formula is used to calculate side A?

• a^2 = b^2 + c^2 - 2bc cos A

• a^2 = b^2 + c^2 + 2bc cos A

• a^2 = b^2 - c^2 - 2bc cos A

• a^2 = b^2 - c^2 + 2bc cos A

What is the calculated length of side A?

• 20.45

• 18.59

• 15.30

• 22.10

Which law is used to find angle C?

• Law of Cosines

• Law of Sines

• Pythagorean Theorem

• Angle Sum Theorem

What is the value of angle C?

• 23.79 degrees

• 30 degrees

• 45 degrees

• 60 degrees

How is angle B calculated?

• Using the law of sines

• Using the law of cosines

• Using the angle sum theorem

• Using the Pythagorean theorem

What is the value of angle B?

• 60 degrees

• 45 degrees

• 90 degrees

• 126.21 degrees