Intro to Trigonometry Module:
Basic Elements of Right Triangle Trigonometry

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Partnership Illinois

  Intro to Trigonometry Lesson
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Problem Description

The Problem

Problem Description

You currently work for your hometown's fire department. They have placed you in charge of buying a new ladder for the department. You need to find out, how tall a ladder to purchase so that you'll be able to reach the top of any building in town. The tallest building is ten stories high. How tall a ladder do you have to buy?

In this module students will,
investigate trigonometric ratios
examine the graphs of simple trig functions
investigate the connections between various trig identities

To be able to find the height of the ladder that you need to buy, it is necessary to use trig. Our problem can be described in the following picture.

The above diagram shows the building and a ladder leaning against it. The height of the building is 10 stories (remember that a story is equal to 10 feet). Therefore, the building is 100 ft tall. Notice how the ground, the building and the ladder form three sides of a triangle.

Questions to think about:

1. Why don't we just buy a 100 foot ladder?
2. Think about the Pythagorean Theorem and how it could be used for this problem.

To help us solve this problem, we are going to use a Geometer's Sketchpad file. If needed a short tutorial is provided if the student is unfamiliar with Geometer's Sketchpad.

GSP - Tutorial.

Otherwise, Continue the Lesson with Worksheet 1.