What Is the Area Formulas?(With Examples)

Area is the measure of the space inside a two-dimensional shape. It tells you how much surface the shape covers and is measured in square units (cm², m², in², ft², etc.). Different shapes have different formulas for calculating their area.

Grades 4-7Key Stage 2-3Årskurs 4-7Klasse 4-7

📖Definition

Area is the measure of the space inside a two-dimensional shape. It tells you how much surface the shape covers and is measured in square units (cm², m², in², ft², etc.). Different shapes have different formulas for calculating their area.

📐Formula

Rectangle: A = l × w; Triangle: A = ½ × b × h; Circle: A = πr²

Each shape has a specific formula: rectangles use length times width, triangles use half of base times height, circles use pi times radius squared.

📝Step-by-Step Guide

1

Identify the Shape

Determine what type of shape you're working with to choose the correct formula.

2

Identify the Measurements Needed

Rectangle needs length and width; triangle needs base and height; circle needs radius.

3

Apply the Formula

Substitute the measurements into the appropriate area formula.

4

Include Square Units

Always write the answer with square units (cm², m², etc.).

⚠️Common Mistakes to Avoid

  • Confusing area with perimeter
  • Forgetting to use square units
  • Using diameter instead of radius for circles
  • Using the slant height instead of perpendicular height for triangles
  • Not converting units before calculating

✏️Practice Problems

Easy

Find the area of a rectangle with length 8 cm and width 5 cm

Answer: 40 cm²

Medium

Find the area of a triangle with base 12 m and height 7 m

Answer: 42 m²

Hard

Find the area of a circle with radius 6 cm (use π = 3.14)

Answer: 113.04 cm²

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Worked Examples

Curriculum Alignment

CommonCore (6.G.A.1)KS3KMK