Angles of Elevation
An angle of elevation is an angle formed above a horizontal line. We can find and use angles of elevation and
trigonometry to measure unusual or difficult distances.
Today we will use a device called an inclinometer, made up of a protractor, string and washer. It will help us
measure an angle of elevation. Use the picture below to see how an inclinometer is used and answer the
following questions.
1.) If an angle of elevation is an angle formed above a horizontal line, which is the angle of elevation that we
need to measure?__________________________
2.) Which angle will be measured by the inclinometer?__________________
3.) The string and washer will always hang vertical due to gravity. If YZ is a vertical line and XN is our
horizontal line, what can we say about Angle YZX?
4.) If we know angle YZX and our inclinometer measures angle XYZ, how can we find our angle of elevation,
angle X?
5.) Our trigonometry functions will allow us to measure the length of MN, if we know at least one angle and
one other side length. What distance will we need to measure in order to find the height of the tree?
6.) Which trigonometric ratio would you use? Explain.
7.) Finally, our trigonometry functions will help us to find the length of segment MN, but this is not the full
height of the tree, h. What is the difference between MN and h that will need to be taken into account after
finding MN?
8.) We will now go outside and measure the height of a difficult object. Keep in mind all the steps we need to
remember from questions 1-7.
a. What object will you measure?
b. Draw a diagram to describe what you measured and what you found. Include all calculations
required to find the height of your object.