Grades Grade 3 GeometryExploring Area with Unit Squares

Exploring Area with Unit Squares

🔷 Geometry

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Exploring Area with Unit Squares

Area is the number of same-size squares that fill a shape — no gaps, no overlaps!

We measure AREA by counting how many UNIT SQUARES fit inside a shape. A unit square is a square with sides of length 1 unit. When we tile a shape with unit squares, every square must be the same size, and there can be no gaps or overlaps.

A 5 × 3 rectangle filled with unit squares:

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5 columns × 3 rows = 15 unit squares → Area = 15 square units.

A = l \times w = 5 \times 3 = 15 \text{ square units}

🏠Area of an L-shaped room

An L-shape can be split into two rectangles.
Top rectangle: 4 × 2 = 8 sq units
Bottom rectangle: 2 × 3 = 6 sq units
Total area: 8 + 6 = 14 square units

Finding area by decomposing shapes:

1Split the irregular shape into simple rectangles

2Find the area of each rectangle (l × w)

3Add all the rectangle areas together

4Label your answer in square units!

Two rectangles with the SAME area

2 × 6 = 12 sq units3 × 4 = 12 sq units

Different perimeters

2+6+2+6 = 16 units3+4+3+4 = 14 units

Same area does NOT mean same perimeter — shapes can have equal areas but different perimeters!

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Remember This!

If you cannot multiply yet, just count the unit squares one by one. Then look for rows and columns — multiplying rows × columns is a fast shortcut!

✏️ Try It!

A shape is made by joining a 3 × 4 rectangle with a 2 × 2 square. What is the total area?

Take Quiz 📝 — 25 Questions