# 4th Grade, Activity 419: Geometric Measurement: Understand Concepts of Angle and Measure Angles

Recognize angles as geometric shapes that are formed wherever two rays share a common endpoint, and understand concepts of angle measurement:

c. An angle that turns through n one-degree angles is said to have an angle measure of n degrees.

### How Many Angles of n Degrees Can Make a Full Turn?

• Group: Whole Class/Alone
• Materials: How Many Angles of n Degrees Can Make a Full Turn sheet

Explain that an angle is measured with reference to a circle with its center at the common endpoint of the rays. Point out that an angle that turns through 1/360 of a circle is called a one-degree angle and can be used to measure angles. Explain that the angles have the same measure. Issue a How Many Angles of n Degrees Can Make a Full Turn sheet to each student. Explain that the angles in the circles are congruent. Instruct students to write the measure of each angle. Then have them write the number of angles of n degrees make a full turn. Emphasize that a full turn is 360°. Help students understand that they can divide 360 by the number of congruent sectors in a circle to find the measure of each congruent angle. Ask questions like the ones below:

• How many 90⁰ angles does it take to make a full turn? (4)
• How many 120⁰ angles does it take to make a full turn? (3)
• How many 60⁰ angles does it take to make a full turn? (6)