Chapter 6 · Let's practise geometry
Lesson 6.1 · Perimeter (1)
Hua's Classroom for Shanghai Maths — One Lesson One Exercise (English edition, pages 109–111).
Lesson Alignment
How this Shanghai Maths lesson connects to learning goals, Common Core, and Eureka Math.
Learning Objectives
Students will be able to:
- 01Trace the edge of shapes to feel perimeter. (Question 1)
- 02Calculate perimeter on a grid. (Question 2)
- 03Solve laps around a regular polygon. (Question 3)
Common Core Standards
| Code | Standard (focus for this lesson) |
|---|---|
| 3.MD.D.8 | Solve problems involving perimeters of polygons. |
Eureka Math Correspondence
| Shanghai Maths | Focus | Eureka Math |
|---|---|---|
| Perimeter | Around | G3 M7 |
| Grid | Count units | G3 M7 |
Core Concepts
Perimeter is the distance around a shape.
What is Perimeter?
The total length of the boundary (edge) of a shape.
Grid Perimeters
Count outer unit segments carefully — do not count inner lines.
Laps & Polygons
Regular pentagon side 30 m × 5 × 6 laps = distance run.
Key Terms & Definitions (Reference)
Quick glossary for this lesson.
| Term | Definition |
|---|---|
| Perimeter | Distance around a shape. |
| Regular polygon | All sides equal. |
Key Answers
Quick reference for this lesson’s exercise answers.
Key answers
- Trace edges (drawing).
- Multiple choice: (1) B (rope); (2) A (straight ruler).
- Grid perimeters (1 m squares): Shape 1: 14 m; Shape 2: 16 m; Shape 3: 20 m; Shape 4: 24 m.
- Perimeters: triangle 17 cm; quadrilateral 17 dm; parallelogram 26 dm; regular hexagon 54 m.
- Pond: $30\times5\times6=900$ m.
- Enhancement: 5 combinations; shortest perimeter 8 cm.