The trigonometric ratios are ratios between each pair of lengths in a right-angled triangle.

Choosing the right trigonometric ratio

Maths

Checking and securing understanding of similar triangles

Checking and securing understanding of Pythagoras' theorem

The unit circle

Scaling the right-angled triangle from the unit circle

Sine and cosine ratios

Tangent ratio

Using the sine ratio

Using the cosine ratio

Using the tangent ratio

Choosing an appropriate method for finding lengths of a triangle

Problem solving with trigonometry

In this unit, pupils were introduced to the trigonometric ratios and developed the skills to ascertain which ratio would be appropriate for a given problem. In the future unit, pupils are introduced to a variety of situations where this knowledge is required, such as 3-D problems and elevation/depression.

In the prior unit, pupils continued to build on their understanding of congruence and similarity with right-angled triangles. In this unit, similarity is used to extend a right-angled triangle in the unit circle to any other right-angled triangle.

In this unit pupils learn how to recognise the relationship between the unit circle and the trigonometric ratios of sine, cosine and tangent. Pupils then apply this knowledge to solve trigonometric problems.

Trigonometry

There is not enough information to solve this problem.

Tick which approaches could be used to find $$x$$ without finding further sides or angles given the information provided in the diagram.

Tick which approaches could be used to find $$x$$ given the information provided in the diagram.

Tick which approaches could be used to find $$x$$ without finding more angles and given the information provided in the diagram.

Tick which approaches could be used to find the angle without finding the remaining side, given the information provided in the diagram.

Tick which approach is the simplest to find $$x$$ given the information provided in the diagram.

It is not possible to know whether the triangles are similar or not.

Which of the following statements is true for these triangles?

For sin(xᵒ) = y, which of these statements is true? 

In a right triangle, if the hypotenuse is 50 cm and a second side is 30 cm, what is the area? (Use a calculator to help you.)

Choosing the right trigonometric ratio

Lesson outcome