Unit Plan 14 (Grade 4 Math): Lines, Rays, Angles, and Parallel/Perpendicular
Draw and classify points, lines, segments, rays, and angles; identify right, acute, and obtuse angles; and mark parallel and perpendicular lines using clear labels and precise geometric notation.
Focus: Draw and identify points, lines, line segments, rays; classify right, acute, obtuse angles; recognize parallel and perpendicular lines and use clear markings/labels.
Grade Level: 4
Subject Area: Mathematics (Geometry • Measurement & Data connection)
Total Unit Duration: 5 sessions (one week), 45–60 minutes per session
I. Introduction
Students build a precise geometry vocabulary and learn to draw, label, and classify foundational objects: points, lines, segments, rays, and angles. They practice identifying parallel and perpendicular lines in grids, diagrams, and real-world photos, using consistent symbols and naming conventions to communicate clearly.
Essential Questions
- How do I name and draw geometric objects so others can understand my diagram?
- What makes an angle right, acute, or obtuse, and how can I tell without measuring degrees?
- How do I recognize and clearly show parallel and perpendicular lines in a drawing?
II. Objectives and Standards
Learning Objectives — Students will be able to:
- Draw and label points, lines, line segments, and rays with appropriate endpoints/arrowheads.
- Construct and classify angles as right, acute, or obtuse using benchmarks (e.g., a square corner).
- Identify and mark parallel and perpendicular lines in grids, figures, and classroom images.
- Use naming conventions (e.g., point names, angle names) and markings (tick marks, right-angle squares, parallel arrows) consistently.
- Explain how they know (reasoning) when a figure shows a given relationship.
Standards Alignment — CCSS Grade 4 (spiral across the unit)
- 4.G.1: Draw points, lines, line segments, rays, angles (right, acute, obtuse), and identify these in two-dimensional figures; identify parallel and perpendicular lines.
- Connections: 4.MD.5–4.MD.6 (angle concepts and sketches, light preview); MP.1–MP.8 threaded.
Success Criteria — Student Language
- I can draw and label points, lines, segments, rays, and angles correctly.
- I can tell whether an angle is right, acute, or obtuse and show my evidence.
- I can mark parallel/perpendicular lines and explain how I know.\