How to apply the law of cosines with no angles given

The video tutorial covers the process of solving triangle problems using the law of sines and the law of cosines. It begins with an introduction to triangle angles and the conditions under which these laws can be applied. The instructor explains how to find obtuse angles and the importance of identifying the correct angle to avoid multiple solutions. The tutorial includes detailed calculations for finding angles and sides, emphasizing the use of inverse trigonometric functions. The session concludes with a method to find the remaining angles using the known values.

Why can't the law of sines be applied directly in the given triangle problem?

• Because the triangle is not a right triangle.

• Because all sides are equal.

• Because not all angles are known.

• Because all angles are known.

What is the maximum number of obtuse angles a triangle can have?

• Three

• Two

• None

• One

Which law is used to find an angle when the law of sines is not applicable?

• Law of Secants

• Law of Tangents

• Law of Cosines

• Law of Cotangents

What is the first step in using the law of cosines to find an angle?

• Find the sine of the angle.

• Calculate the square of the side opposite the angle.

• Add all the sides of the triangle.

• Subtract the known angles from 180 degrees.

After finding one angle using the law of cosines, what is the next step?

• Use the law of sines to find another angle.

• Recalculate the sides of the triangle.

• Use the law of tangents to find another angle.

• Assume the triangle is equilateral.

How can the third angle of a triangle be found once two angles are known?

• By using the law of cosines again.

• By subtracting the sum of the two known angles from 180 degrees.

• By measuring it directly.

• By using the Pythagorean theorem.

What is the advantage of having a ratio in a triangle problem?

• It ensures all sides are equal.

• It eliminates the need for any calculations.

• It makes the triangle a right triangle.

• It allows for the use of the law of sines.