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Finding Measurement of Angles: 4th Grade Lesson

written by: Donna Ventura • edited by: Carly Stockwell • updated: 11/12/2013

Students will investigate the concept of angles and determine the measurement of angles using a cut-out of a one-degree of a circle.

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    Identify a “one-degree angle" as an angle that turns through 1/360 of a circle. This angle can be used to determine the measurement of angles. Go to the bottom of the article to download a copy of the lesson.

    Lesson Objective: The lesson is aligned to the Common Core State Standards for Mathematics – 4MD.5a and b Geometric Measurement – Recognize angles as geometric shapes that are formed wherever two rays share a common endpoint.

    Materials Required: Cutout of one-degree angle

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    Lesson Procedure:

    Identifying Measurement of an Angle using a “One-Degree Angle"

    Look at the circle below. Point O is the center of the circle. Both Ray a and Ray b share a common endpoint, Point O. Ray a and Ray b form an angle. Ray a and Ray b are the sides of the angle. The angle on the circle turns through 1/360 of the circle. This angle is called a “one-degree angle". This angle measures one degree.

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    Student Work

    Cutout the “one-degree angle” above. Use the “one-degree angle” to draw angles with the following measurements.

    1. On your paper, draw an angle that measures 3 degrees.
    2. On your paper, draw an angle that measures 5 degrees.
    3. On your paper, draw an angle that measures 8 degrees.
    4. On your paper, draw an angle that measures 10 degrees.
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    Individual or Group Work:

    Use the “one-degree angle" that you cutout from the activity above to draw angles with the following measurements.

    1. On your paper, draw a circle. Label the center of the circle with Point O. Draw Ray a and Ray b to form an angle with endpoints at the center of the circle and measures 2 degrees.
    2. On your paper, draw a circle. Label the center of the circle with Point O. Draw Ray f and Ray g to form an angle with endpoints at the center of the circle and measures 4 degrees.
    3. On your paper, draw a circle. Label the center of the circle with Point O. Draw Ray m and Ray n to form an angle with endpoints at the center of the circle and measures 7 degrees.
    4. On your paper, draw a circle. Label the center of the circle with Point O. Draw Ray p and Ray q to form an angle with endpoints at the center of the circle and measures 9 degrees.

    Answer the following two questions for each of the shaded angles shown below.

    • How many “one-degree angles" did you use to measure each of the shaded angles?
    • How many degrees do the shaded angles measure?
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    Answers:

    1. Students should trace around the “one-degree angle” three times to draw an angle that measures approximately 2 degrees.
    2. Students should trace around the “one-degree angle” five times to draw an angle that measures approximately 4 degrees.
    3. Students should trace around the “one-degree angle” eight times to draw an angle that measures approximately 7 degrees.
    4. Students should trace around the “one-degree angle” ten times to draw an angle that measures approximately 9 degrees.
    5. 14 “one-degree angles”, 14 degrees
    6. 28 “one-degree angles”, 28 degrees

    Students should be able to draw and measure angles with a specified measurement using a model of a “one-degree angle”.

    Download a copy of the lesson.

Finding the Measurement of Angles: 4th Grade Lessons

These three lessons will have students learn to find the measurement of angles by using protractors, addition and subtraction. These math lessons all meet Common Core objectives.
  1. Finding Measurement of Angles: 4th Grade Lesson
  2. Finding the Measurement of Angles using a Protractor: 4th Grade Lesson
  3. Finding Measurement of Angles through Addition and Subtraction: 4th Grade Lesson