Lesson 3

1. Lesson 3

1.5. Explore

Mathematics 20-3 Module 4

Module 4: The Right Kind Of Triangles

Explore

In Discover you may have noticed that you used the tangent ratio to determine the height of a tall object. Later in this lesson you will become aware of the relationship between the tangent ratio and angles of elevation and depression.

You may recall from previous mathematics courses that there are three basic trigonometric ratios:

tangent ratio
sine ratio
cosine ratio

If θ is the measure of an acute angle of a right triangle, the sides in reference to this angle would be labelled as shown in the diagram. The sine, cosine, and tangent ratios for θ are also shown.

This is an illustration of the three trigonometric ratios.

The memory aid SOH-CAH-TOA can be used to help remember these ratios.

Sin is Opposite over Hypotenuse; Cos is Adjacent over Hypotenuse; Tan is Opposite over Adjacent.

Try This 2

This play button opens Exploring Trig Ratios – Use It.

Work through Exploring Trig Ratios – Use It to review how the trigonometry ratios are used to calculate missing sides and angles.