Angles in Shapes

Overview

Lesson 5 of 15 in Shapes, Space and Reasoning. In a small group of five, learners identify, compare and describe angles in familiar two-dimensional shapes using visual, tactile and body-based representations.

Learning intentions

• WALT recognise angles at the vertices of familiar shapes.
• WALT compare angles as smaller, larger, right, acute or obtuse where appropriate.
• WALT use visual and physical evidence to explain how angles are alike or different.
• WALT communicate mathematical thinking using drawings, gestures, models and words.

Success criteria

• I can locate angles at the corners of familiar shapes.
• I can compare two angles using visual evidence.
• I can identify a right angle and recognise angles that are acute or obtuse.
• I can explain or show how I know.

Curriculum links

• Geometry: identify, describe and classify two-dimensional shapes using properties such as sides, vertices and angles.
• Geometry: recognise and compare angle size, including right, acute and obtuse angles.
• Mathematical processes: communicate, justify and represent mathematical ideas in different ways.
• Key competencies: thinking; using language, symbols and texts; managing self; participating and contributing.

Lesson structure (60 minutes)

1. 0–7 minutes – Visual hook and prior knowledge Open with the angle investigation introduction. Display photographs or simple drawings of a door opening, book corner and road sign. Ask learners to silently point to an angle, then show with their arms whether it is smaller, the same as, or larger than a square corner. Accept gestures, drawing or signing as responses.

2. 7–17 minutes – Model angle language Use a large angle template and demonstrate that an angle is the turn or opening between two rays meeting at a vertex. Model a right angle using a square corner, then compare acute angles as smaller than a right angle and obtuse angles as larger than a right angle but smaller than a straight angle. Use the visual examples in the angle investigation introduction and check understanding after each example by asking learners to hold up one of three prepared angle cards or point to the matching image.

3. 17–30 minutes – Tactile and body-angle exploration Give each learner two strips joined with a split pin, or an angle template. Call or display prompts such as “make a right angle”, “make an acute angle” and “make an obtuse angle”. Learners create the angle, then compare it with a square corner or right-angle template. Include arm positions as an optional body model, ensuring learners can participate through tactile resources and visual demonstration rather than spoken explanation.

4. 30–44 minutes – Shape investigation Provide the cut-apart 2D shape property cards and familiar classroom shapes. Learners take turns selecting a shape, tracing or touching each vertex, and locating its angles. They sort or discuss the angles as right, acute, obtuse or “not sure yet”, using the right-angle template as evidence. Prompt with: “Which angle is smaller?”, “How can you tell?” and “Are all the angles the same?” Keep the group together so each learner can see the demonstration and classmates’ evidence.

5. 44–54 minutes – Independent evidence task Distribute the angles in shapes investigation sheet. Learners identify angles on familiar shapes, compare pairs of angles and record evidence by circling, drawing, matching or writing. Year 4 learners may classify clearly marked angles; Year 5–6 learners should also explain how a right-angle template or visual comparison supports their decision. Confer individually and use pointing, modelling and written prompts instead of relying on oral explanations.

6. 54–60 minutes – Share and check Return to the angle investigation introduction for the final comparison images. Each learner shares one finding by showing a shape, pointing to an angle, drawing it or explaining it. Finish with the visual prompt: “Show me a shape with a right angle” and “Show me an angle larger than a right angle.” Record any misconceptions to revisit in Lesson 6.

Resources

• the angle investigation introduction — one visual deck used throughout the lesson.
• the angles in shapes investigation sheet — one-page individual evidence task.
• 2D shape property cards — hands-on familiar shape cards.
• Large right-angle template or card corner.
• Several acute, right and obtuse angle templates.
• Two card strips joined with split pins for each learner.
• Familiar classroom objects or photographs showing corners and openings.
• High-contrast overlays, thick dark outlines and uncluttered visual examples.
• Whiteboard and markers.

Assessment

• Observe whether learners locate the vertex and compare angle openings accurately during the tactile activity.
• Use questioning, pointing and demonstrations to check whether learners distinguish acute, right and obtuse angles.
• Review the worksheet for correct classifications and visual or written evidence. Note learners who need further modelling, particularly those confusing side length with angle size.

Differentiation

• Support learners with physical angle models, a large right-angle template, high-contrast overlays, enlarged shapes and teacher modelling. Mark each vertex clearly and allow tracing or touching.
• Reduce the number of shapes and provide two-choice comparisons before introducing the terms acute and obtuse.
• For Deaf learners and others who benefit from visual access, face the group, keep instructions displayed, use visual demonstrations and provide frequent checks for understanding through pointing, modelling and show-me responses.
• Extend advanced learners by investigating which familiar shapes contain right angles and proving their findings with a template, tracing, labelled diagrams or a written explanation. Ask whether a shape can contain more than one type of angle.