Shark Learning
Fourth/Geometry

Find the Missing Side from Area

Find a missing side length when the area and one side are given.
0
Sheets
1847
Views
452
Downloads
Study Guide

Preview

Find the Missing Side from Area preview

Tap to open PDF

Practice Questions

  1. A rectangle has area 18 cm². Its length is 3 cm. What is the other side?
    Show answer

    6 cm

  2. A rectangle has area 20 ft². Its width is 5 ft. What is the other side?
    Show answer

    4 ft

  3. A rectangle has area 21 cm². Its length is 7 cm. What is the other side?
    Show answer

    3 cm

  4. A rectangle has area 24 ft². Its width is 6 ft. What is the other side?
    Show answer

    4 ft

  5. A rectangle has area 16 cm². Its length is 4 cm. What is the other side?
    Show answer

    4 cm

Quick Tip
Tip: If Area = L × W and L is given, then W = Area ÷ L (and the other way too).
Teacher Resources
Teaching Notes

Introduce area as covering a surface and connect it to multiplication. Emphasize that finding a missing side requires the inverse operation, division.

Vocabulary
Missing side: The side length not given.
Division: Splitting into equal parts.
Common Mistakes
  • Confusing area with perimeter calculations.
  • Incorrect multiplication or division fact recall.
  • Multiplying dimensions when division is needed for a missing side.
Differentiation
SupportUse grid paper or concrete manipulatives to visualize the area.
ChallengeExplore composite shapes or problems involving fractional side lengths.
Discussion Questions
  • How does knowing the area help us find a missing side?
  • Can you think of a real-world situation for this skill?
  • What is the relationship between multiplication and division here?
  • How is this like finding a missing factor in an equation?
Extension Activities
  • Find missing sides with decimals.
  • Use area to find perimeter.
  • Create problems for others.
Parent Tip

Give your child a rectangular placemat and ask them to find a missing side if you give the area.

Learning Path
Skill Cluster

Geometry and Measurement

Estimated Time

15 minutes

Skills Practiced
Find missing side areaUse division in geometryRelate area and sides