Grade 3 · Measurement & Data · MAT-03-MD-010
Find Rectangle Area with Multiplication
Represent find rectangle area with multiplication with words, symbols, diagrams, or models appropriate to Grade 3.
Learning objectives
What you should be able to do
- Represent find rectangle area with multiplication with words, symbols, diagrams, or models appropriate to Grade 3.
- Solve problems involving find rectangle area with multiplication accurately and explain why the method works.
- Check results for reasonableness using a second representation, inverse relationship, benchmark, or property when appropriate.
Prerequisite check
Make sure the foundation is ready.
Checks conceptual readiness before new Grade 3 reasoning.
Checks whether prior skills are available for use, not only recalled by name.
Learn
Build the idea from meaning, not memorization.
Meaning of Find Rectangle Area with Multiplication
A rectangle tiled with unit squares forms equal rows and columns, so its area equals length times width.
A reliable reasoning strategy
Identify the number of rows and columns of unit squares, multiply them, and label the result in square units.
Representations that should agree
Rectangle area connects arrays, multiplication, and geometric measurement. A correct model, equation, verbal explanation, or diagram should preserve the same quantities and relationships.
How to check the result
Check whether the answer fits the quantities, units, and structure of the problem. Use a second representation or inverse relationship when available, and explain what would make an answer unreasonable.
Interactive math lab
Change it. See what stays true.
Array Builder
Build equal rows and columns, then connect the grid to repeated addition.
- build a model
- change one quantity
- predict before calculating
- explain why the result changes
Worked examples
Twenty different ways to see the concept work.
A rectangle is 3 units by 5 units. What is its area?
3 × 5 = 15The rectangle has equal rows and columns of unit squares.
A rectangle is 4 units by 8 units. What is its area?
4 × 8 = 32The rectangle has equal rows and columns of unit squares.
A rectangle is 5 units by 4 units. What is its area?
5 × 4 = 20The rectangle has equal rows and columns of unit squares.
A rectangle is 6 units by 7 units. What is its area?
6 × 7 = 42The rectangle has equal rows and columns of unit squares.
A rectangle is 7 units by 3 units. What is its area?
7 × 3 = 21The rectangle has equal rows and columns of unit squares.
A rectangle is 8 units by 6 units. What is its area?
8 × 6 = 48The rectangle has equal rows and columns of unit squares.
A rectangle is 9 units by 2 units. What is its area?
9 × 2 = 18The rectangle has equal rows and columns of unit squares.
A rectangle is 2 units by 5 units. What is its area?
2 × 5 = 10The rectangle has equal rows and columns of unit squares.
A rectangle is 3 units by 8 units. What is its area?
3 × 8 = 24The rectangle has equal rows and columns of unit squares.
A rectangle is 4 units by 4 units. What is its area?
4 × 4 = 16The rectangle has equal rows and columns of unit squares.
A rectangle is 5 units by 7 units. What is its area?
5 × 7 = 35The rectangle has equal rows and columns of unit squares.
A rectangle is 6 units by 3 units. What is its area?
6 × 3 = 18The rectangle has equal rows and columns of unit squares.
A rectangle is 7 units by 6 units. What is its area?
7 × 6 = 42The rectangle has equal rows and columns of unit squares.
A rectangle is 8 units by 2 units. What is its area?
8 × 2 = 16The rectangle has equal rows and columns of unit squares.
A rectangle is 9 units by 5 units. What is its area?
9 × 5 = 45The rectangle has equal rows and columns of unit squares.
A rectangle is 2 units by 8 units. What is its area?
2 × 8 = 16The rectangle has equal rows and columns of unit squares.
A rectangle is 3 units by 4 units. What is its area?
3 × 4 = 12The rectangle has equal rows and columns of unit squares.
A rectangle is 4 units by 7 units. What is its area?
4 × 7 = 28The rectangle has equal rows and columns of unit squares.
A rectangle is 5 units by 3 units. What is its area?
5 × 3 = 15The rectangle has equal rows and columns of unit squares.
A rectangle is 6 units by 6 units. What is its area?
6 × 6 = 36The rectangle has equal rows and columns of unit squares.
Practice
Guided practice with hints
01A rectangle is 9 units by 4 units. What is its area?
Hint: Identify the number of rows and columns of unit squares, multiply them, and label the result in square units.
Answer: 36 square units
02A rectangle is 2 units by 7 units. What is its area?
Hint: Identify the number of rows and columns of unit squares, multiply them, and label the result in square units.
Answer: 14 square units
03A rectangle is 3 units by 3 units. What is its area?
Hint: Identify the number of rows and columns of unit squares, multiply them, and label the result in square units.
Answer: 9 square units
04A rectangle is 4 units by 6 units. What is its area?
Hint: Identify the number of rows and columns of unit squares, multiply them, and label the result in square units.
Answer: 24 square units
05A rectangle is 5 units by 2 units. What is its area?
Hint: Identify the number of rows and columns of unit squares, multiply them, and label the result in square units.
Answer: 10 square units
06A rectangle is 6 units by 5 units. What is its area?
Hint: Identify the number of rows and columns of unit squares, multiply them, and label the result in square units.
Answer: 30 square units
Practice
Independent practice
01A rectangle is 5 units by 8 units. What is its area?
Answer: 40 square units
02A rectangle is 6 units by 4 units. What is its area?
Answer: 24 square units
03A rectangle is 7 units by 7 units. What is its area?
Answer: 49 square units
04A rectangle is 8 units by 3 units. What is its area?
Answer: 24 square units
05A rectangle is 9 units by 6 units. What is its area?
Answer: 54 square units
06A rectangle is 2 units by 2 units. What is its area?
Answer: 4 square units
07A rectangle is 3 units by 5 units. What is its area?
Answer: 15 square units
08A rectangle is 4 units by 8 units. What is its area?
Answer: 32 square units
Common mistakes
Learn to catch the error, not just the answer.
Use multiplication for the interior array and square units for the result.
Reconnect the answer to find rectangle area with multiplication and verify that the model, calculation, and label describe the same quantity.
Applications & challenge
Use the idea beyond a single exercise.
Applications
- Find material needed to cover rectangular surfaces.
- Use find rectangle area with multiplication to interpret or solve a Grade 3 situation with quantities, diagrams, measurements, or data.
Challenge problems
A rectangle is 9 units by 5 units. What is its area?
45 square units
A rectangle is 2 units by 8 units. What is its area?
16 square units
A rectangle is 3 units by 4 units. What is its area?
12 square units
A rectangle is 4 units by 7 units. What is its area?
28 square units
Flashcards
Retrieve it from memory.
Flashcards
Card 1 of 4
Game mode
Find Rectangle Area with Multiplication Challenge
Solve and explain Grade 3 problems involving find rectangle area with multiplication without relying on answer guessing.
Practice
Mastery check
01A rectangle is 5 units by 2 units. What is its area?
Answer: 10 square units
02A rectangle is 6 units by 5 units. What is its area?
Answer: 30 square units
03A rectangle is 7 units by 8 units. What is its area?
Answer: 56 square units
04A rectangle is 8 units by 4 units. What is its area?
Answer: 32 square units
05A rectangle is 9 units by 7 units. What is its area?
Answer: 63 square units
06A rectangle is 2 units by 3 units. What is its area?
Answer: 6 square units
07A rectangle is 3 units by 6 units. What is its area?
Answer: 18 square units
08A rectangle is 4 units by 2 units. What is its area?
Answer: 8 square units
Terminology
Words to know
- length
- A measure of one side dimension.
- width
- A measure of the perpendicular side dimension.
Continue learning
Connected concepts
Curriculum references
Standards and instructional references
California Common Core State Standards for Mathematics — Grade 3, 3.MD.7.a-b
Primary standards alignment for Find Rectangle Area with Multiplication.2023 Mathematics Framework for California Public Schools
Instructional emphasis on reasoning, representations, problem solving, and equitable access.