Sine Ratio Problems

In these lessons, we will learn how to find the angles and sides using the sine ratio and how to solve word problems using the sine ratio.

Hints on solving trigonometry problems:

• If no diagram is given, draw one yourself.
• Mark the right angles in the diagram.
• Show the sizes of the other angles and the lengths of any lines that are known
• Mark the angles or sides you have to calculate.
• Consider whether you need to create right triangles by drawing extra lines. For example, divide an isosceles triangle into two congruent right triangles.
• Decide whether you will need Pythagoras theorem, sine, cosine or tangent.
• Check that your answer is reasonable. The hypotenuse is the longest side in a right triangle.

Example:

Calculate the length of the side x, given that sin θ = 0.6

Solution:

Using Pythagoras’ theorem:

Find Missing Sides

Find the missing length of a triangle using the sine function
These two videos show you how to find the missing length of a triangle using the sine function.
We are given a right triangle and two side lengths and a missing length.
We show a right triangle and label the hypotenuse, and two legs the opposite side and adjacent side according to their relation to θ.