Reasoning about Angles (Part 1)
10 min
Narrative
This Warm-up prompts students to carefully analyze and compare geometric features of four clock faces. Students may compare the times being represented, but because no numbers are shown, they likely will compare the hands of the clocks and the angles they form.
In making comparisons, students have a reason to use language precisely (MP6). Teachers have a chance to hear the terminology students use to talk about the characteristics of angles.
Launch
- Groups of 2
- Display the image.
- “Pick 3 clock faces that go together. Be ready to share why they go together.”
Teacher Instructions
- 1 minute: quiet think time
- 2–3 minutes: partner discussion
- Record responses.
- As students explain, find opportunities to reinforce the terms “acute” and “obtuse.”
Student Task
Which 3 go together?
Sample Response
Sample responses:
A, B, and C go together because:
- They have 2 obvious segments.
- Their hands point in different directions.
A, B, and D go together because:
- They could be times in the afternoon.
- They could be times in the middle of the night.
A, C, and D go together because:
- The minute hand is pointing up.
- The time is within a few minutes of the hour.
B, C, and D go together because:
- The number of minutes in the time is more than 0.
Activity Synthesis (Teacher Notes)
- Display the following sentences and ask students to complete each sentence with “always,” “sometimes,” or “never”:
- “The hour and minute hands of a clock _____ form one angle.”
- “The hour and minute hands of a clock _____ form two angles.”
- Ask students to explain their choice or use counterexamples to disagree with other students' choice.
Standards
- 4.G.1·Draw points, lines, line segments, rays, angles (right, acute, obtuse), and perpendicular and parallel lines. Identify these in two-dimensional figures.
- 4.G.A.1·Draw points, lines, line segments, rays, angles (right, acute, obtuse), and perpendicular and parallel lines. Identify these in two-dimensional figures.
15 min
20 min
Knowledge Components
All skills for this lesson
No KCs tagged for this lesson
Reasoning about Angles (Part 1)
10 min
Narrative
This Warm-up prompts students to carefully analyze and compare geometric features of four clock faces. Students may compare the times being represented, but because no numbers are shown, they likely will compare the hands of the clocks and the angles they form.
In making comparisons, students have a reason to use language precisely (MP6). Teachers have a chance to hear the terminology students use to talk about the characteristics of angles.
Launch
- Groups of 2
- Display the image.
- “Pick 3 clock faces that go together. Be ready to share why they go together.”
Teacher Instructions
- 1 minute: quiet think time
- 2–3 minutes: partner discussion
- Record responses.
- As students explain, find opportunities to reinforce the terms “acute” and “obtuse.”
Student Task
Which 3 go together?
Sample Response
Sample responses:
A, B, and C go together because:
- They have 2 obvious segments.
- Their hands point in different directions.
A, B, and D go together because:
- They could be times in the afternoon.
- They could be times in the middle of the night.
A, C, and D go together because:
- The minute hand is pointing up.
- The time is within a few minutes of the hour.
B, C, and D go together because:
- The number of minutes in the time is more than 0.
Activity Synthesis (Teacher Notes)
- Display the following sentences and ask students to complete each sentence with “always,” “sometimes,” or “never”:
- “The hour and minute hands of a clock _____ form one angle.”
- “The hour and minute hands of a clock _____ form two angles.”
- Ask students to explain their choice or use counterexamples to disagree with other students' choice.
Standards
- 4.G.1·Draw points, lines, line segments, rays, angles (right, acute, obtuse), and perpendicular and parallel lines. Identify these in two-dimensional figures.
- 4.G.A.1·Draw points, lines, line segments, rays, angles (right, acute, obtuse), and perpendicular and parallel lines. Identify these in two-dimensional figures.