VocabularyRight Angle: An angle at 90 degrees
Acute Angle: An angle less than 90 degrees Obtuse Angle: An Angle more than 90 degrees, but less than 180 degrees Straight Angle: An angle at 180 degrees Complementary Angle: Two angles that equal a right angle Supplementary Angle: Two Angles that equal a straight angle |
Today's Target: Be able to identify the various angles, and understand how to find missing angle information.
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Identifying Angles
Angles are the 2 lines that intersect with one another. Depending on how they intersect, changes the angle. Frequently, we use a protractor to find and identify angles as it is a clear tool which we put overtop the lines and measure. The numbers on the protractor are considered "Degrees."
For example, this one goes to 90, and is 90 degrees. |
The main angles
Right AngleThe Right Angle is when, using a protractor, the line goes straight up at 90 degrees. The right angle is identified by the small square. A right angle can only be 90 degrees. 89 or 91 degrees are no longer right angles.
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Acute AngleThe Acute Angle is when, using a protractor, the lines line up with anything less than 90 degrees. From 1 degree to 89 degrees, the angle is classified as an acute angle.
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Obtuse AngleThe Obtuse Angle is when, using a protractor, the lines line up with anything more than 90 degrees but less than 180 degrees. From 91 degree to 179 degrees, the angle is classified as an Obtuse angle.
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Straight AngleThe Straight Angle is when, using a protractor, the lines are straight. A Straight angle is only 180 degrees.
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Letters and Naming
Complementary and Supplementary Angles
Practice
Below are angles that you need to identify and find the missing information for.