1. Lesson 4

1.4. Discover

Mathematics 20-3 Module 4

Module 4: The Right Kind Of Triangles

 

Discover

 

In Lesson 3 you used your clinometer to find the height of a totem pole or another pole, like a light standard. In the next Try This activity you will again look to find the height of a pole, but this time you will not be standing on the ground!

 

Try This 1

 

You are given the following diagram showing a flagpole outside a second-storey window. Use the information in the diagram to answer the following questions.

 

An image describes a word problem. A shared edge of two right triangles is labelled d. At one end, both triangles have right angles, at the other end of the shared side the top triangle has a 31 degree angle and the bottom triangle has a 40 degree angle. The length opposite both these angles in their respective triangles are unknown and labelled x and y.

  1. In the diagram, there is one piece of information missing. What is needed before you can determine the height of the flagpole?

  2. How would you explain the steps involved in solving this type of trigonometric problem?

  3. Why were two triangles used to illustrate and solve this problem? Could the problem have been solved using one triangle? Explain your answer.

course folder Save your work to your course folder.

 

Share 1

 

Share your responses to the questions in Try This 1 with a classmate or in a group.

  • How did the strategy you used to solve this problem compare with others? Would you use the same strategy or change your strategy based on the discussion you’ve had?

  • What are the similarities and differences between the problems in Try This 1 and the Try This 1 in Lesson 3, where you used your clinometer to find the height of a tall object?

course folder If required, save a copy of your discussion and your diagram in your course folder.