Chapter 6 · Let's practise geometry

Lesson 6.3 · Perimeters of rectangles and squares (1)

Hua's Classroom for Shanghai Maths — One Lesson One Exercise (English edition, pages 115–117).

Grade 3 Second Semester Pages 115–117 ECNU Press

Lesson Alignment

How this Shanghai Maths lesson connects to learning goals, Common Core, and Eureka Math.

Learning Objectives

Students will be able to:

  1. 01Fill perimeter and area tables for rectangles. (Question 1)
  2. 02Find P and A from length and width stories. (Question 2)
  3. 03Solve split-rectangle area problems. (Question 3)

Common Core Standards

CodeStandard (focus for this lesson)
3.MD.D.8Perimeter.
3.MD.C.7Area.

Eureka Math Correspondence

Shanghai MathsFocusEureka Math
Formulas2(l+w), 4sG3 M7
TableP and AG3 M4/M7

Core Concepts

Relate length, width, perimeter, and area in tables.

Formulas

Rectangle: $P = 2(l+w)$. Square: $P = 4s$. Area: $A = l \times w$ or $s \times s$.

Fill the Table

Given two measures, find the others.

Stories

Vegetable patch: length 40 m, 5 m longer than width → find P and A.

Key Terms & Definitions (Reference)

Quick glossary for this lesson.

TermDefinition
Length / widthSides of a rectangle.
Side lengthSide of a square.

Key Answers

Quick reference for this lesson’s exercise answers.

Key answers

  1. Tables: rectangles — P 74 cm / A 210 cm²; P 180 cm / A 2000 cm²; P 140 dm / A 600 dm². Squares — P 60 cm / A 225 cm²; side 12 m / A 144 m².
  2. Frame / tetrominoes: side 4 dm; longest perimeter figure 6, shortest figure 2.
  3. Vegetable patch: P 150 m; A 1400 m².
  4. Sports field: length 100 m.
  5. Pool: P 150 m.
  6. Cut square: each rectangle P 32 cm.
  7. Areas A, B: A 550 cm²; B 1650 cm².
  8. Tables seating: 6; at least 8.
  9. Wire 24 cm: 6 rectangles (11×1 … 6×6); areas differ (largest near-square).