1. Module 7

1.24. Page 2

Mathematics 10-3 Module 7 Lesson 5

Module 7: Trigonometry

 

Get Started

 

In this activity you will review the relationship between the two acute angles of a right triangle.

 

Self-Check

 

Work with a partner, if possible.

 

Step 1: Use your protractor and straight edge to draw a right triangle PQR of any size. An example is shown below.

 

 

This illustration shows right triangle PQR. The sides are labelled with lower case p, q, and r so that lowercase p is opposite angle P, lowercase q is opposite angle Q and lowercase r is opposite angle R.

 

Step 2: Measure ∠P and ∠R to the nearest degree.

 

Did You Know

 

The letters used to name triangles are usually placed alphabetically. But the letters really can be in any order. For example, the previous triangle could have been named any of the following: ΔQRP, ΔPRQ, or ΔRQP.

SC 1. Determine ∠P + ∠R.

 

SC 2. Will the sum of the two acute angles of a right triangle always be the same as the answer you obtained in SC 1? Explain.

 

SC 3. What name is given to a pair of angles with this sum?

 

SC 4. In right ΔABC, ∠A and ∠B are acute angles. If ∠B = 47°, what is the size of ∠A? Draw a diagram to support your answer.

 

SC 5. What is the complement of a 60° angle?

 

Compare your answers.