# Lesson 7

The Size of Angles on a Clock

### Lesson Purpose

The purpose of this lesson is for students to describe the size of an angle as a turn of one ray to the other.

### Lesson Narrative

In this lesson, students use an analog clock as a tool to describe the size of angles. They begin by using the clock to help describe how to draw a given angle, which involves describing the positions of the two hands of the clock. This work encourages students to relate the turning of the hands in a circular arc to the turning of rays of an angle around their shared endpoint.

Students then use language that suggests rotational movement to describe and compare the size of angles on a clock. To describe whether an angle is greater or smaller than another, they reference the amount of turn made by one or both rays. Students will connect the ideas developed in this lesson to the standard measurement of an angle (in degrees) in subsequent lessons.

### Learning Goals

Teacher Facing

• Describe the size of an angle as a turn of one ray from the other.
• Use the features of an analog clock to describe and compare the size of angles.

### Student Facing

• Let’s describe angles using the hands of a clock.

### Required Materials

Materials to Gather

Addressing

Building Towards

### Lesson Timeline

 Warm-up 10 min Activity 1 15 min Activity 2 20 min Lesson Synthesis 10 min Cool-down 5 min

### Teacher Reflection Questions

What student questions about angles or angle measurement were addressed in this lesson? What can you do to help students refine their emerging understanding of angle measurement or resolve any questions that were not answered?

### Suggested Centers

• Compare (1–5), Stage 5: Fractions (Supporting)
• Target Measurements (2–5), Stage 4: Degrees (Addressing)

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