50 lines
2.4 KiB
Markdown
50 lines
2.4 KiB
Markdown
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---
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title: Angles Acute Obtuse Straight and Right
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---
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## Angles: Acute, Obtuse, Straight and Right
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There are four types of angles depending on their size in degrees. These are:
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<ul>
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<li>Right angles</li>
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<li>Straight angles</li>
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<li>Acute angles</li>
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<li>Obtuse angles</li>
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</ul>
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<h3>Right angles</h3>
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Right angles are angles that have a measure of exactly 90°. For example, the angle at the corner of a square or rectangle is a right angle. An example of a right angle is below:
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<img width="153" alt="example of a right angle" src="https://user-images.githubusercontent.com/17547686/31929587-4f167f38-b8a5-11e7-8ee7-e76fc239e866.png">
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<h3>Straight angles</h3>
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Right angles are angles that have a measure of exactly 180°. For example, a straight line has a straight angle. An example of a straight angle is below:
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<img width="251" alt="example of a straight angle" src="https://user-images.githubusercontent.com/17547686/31929586-4efbd912-b8a5-11e7-8f43-5d73cca6e2eb.png">
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<h3>Acute angles</h3>
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Acute angles are angles that have a measure of less than 90°. For example, a capital letter "A" has an acute angle. An example of an acute angle is below:
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<img width="171" alt="screen shot 2017-10-24 at 10 22 45" src="https://user-images.githubusercontent.com/17547686/31929585-4ee08266-b8a5-11e7-8af6-9860a8c46e67.png">
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<h3>Obtuse angles</h3>
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Obtuse angles are angles that have a measure of more than 90° but less than 180°. For example, a clock showing 5 o'clock has an obtuse angle. An example of an obtuse angle is below:
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<img width="288" alt="example of an obtuse angle" src="https://user-images.githubusercontent.com/17547686/31929584-4ec4b216-b8a5-11e7-943d-ea74ce460f1b.png">
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<h3>Examples</h3>
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<h4>Example 1</h4>
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What is the measure of the largest integer acute angle?
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<pre>Since acute angles are angles with a measure less than 90°, the largest integer acute angle will have
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a measure of 89°.</pre>
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<h4>Example 2</h4>
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What is the measure of the smallest integer obtuse angle?
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<pre>Since obtuse angles are angles with a measure larger than 90°, the smallest integer obtuse angle will have
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a measure of 91°.</pre>
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<h4>Example 3</h4>
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What is the measure of the angle in a capital letter "L", and what type of angle is it?
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<pre>The measure of the angle in a capital letter "L" is 90°, and the angle is a right angle.</pre>
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## Sources:
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All images were taken from "Angle Types Review." <i>Khan Academy.</i> Accessed: October 24, 2017.
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