Understanding the Sine Rule

The video tutorial explains how to use the sine rule to find missing sides and angles in triangles that do not have a right angle. It introduces the sine and cosine rules, focusing on the sine rule for this session. The tutorial provides step-by-step examples of using the sine rule to calculate a missing side and a missing angle, emphasizing the importance of correctly labeling sides and angles. The video concludes with a brief mention of when to use the sine rule and a preview of the cosine rule for future lessons.

Why do we need alternative rules like the sine and cosine rules?

• Because all triangles are right-angled.

• Because not all triangles have a right angle.

• Because Pythagoras' theorem is always applicable.

• Because they are easier to use than SOHCAHTOA.

What does the sine rule help you find in a triangle?

• Only the angles of a triangle.

• The area of a triangle.

• Only the sides of a triangle.

• Both the sides and angles of a triangle.

In the sine rule, what do the lowercase letters represent?

• Vertices of the triangle.

• Sides of the triangle.

• Angles of the triangle.

• The hypotenuse of the triangle.

In the example of finding a missing side, what was the value of side b?

• 3.0 meters

• 2.5 meters

• 1.8 meters

• 1.5 meters

What is the first step in using the sine rule to find a missing side?

• Find the hypotenuse.

• Use the cosine rule.

• Calculate the area of the triangle.

• Label the sides and angles.

In the example of finding a missing angle, what was the calculated angle?

• 46 degrees

• 87.5 degrees

• 55 degrees

• 80 degrees

What mathematical function is used to find the angle in the sine rule example?

• Inverse cosine

• Inverse sine

• Tangent

• Cosine

What should you do if you want to find a missing angle using the sine rule?

• Use the version of the formula for missing sides.

• Use the version of the formula for missing angles.

• Use the cosine rule instead.

• Use Pythagoras' theorem.

What is ignored when using the sine rule for two parts of a triangle?

• The angle A

• The side b

• The angle C and side c

• The hypotenuse

What will the next video discuss regarding the sine and cosine rules?

• The history of the sine and cosine rules.

• When to use the sine rule and how the cosine rule works.

• How to use the sine rule for right triangles.

• How to derive the sine rule.