Area

Area - Solve mathematical problems with step-by-step solutions.

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Area Calculator

For Common 2D Shapes

Formulas for a Rectangle

  • Area: A = l × w
  • Perimeter: P = 2(l+w)

How the Area Calculator Works

The Area Calculator computes the area of various geometric shapes including circles, rectangles, triangles, trapezoids, parallelograms, ellipses, and more. Area represents the amount of two-dimensional space enclosed within a shape's boundaries and is fundamental in mathematics, construction, land surveying, design, and everyday problem-solving.

Common Area Formulas

Square: A = s2 (where s is the side length)

Rectangle: A = l × w (length times width)

Triangle: A = ½ × b × h (half of base times height)

Circle: A = πr2 (pi times radius squared)

Trapezoid: A = ½ × (b1 + b2) × h (average of bases times height)

Parallelogram: A = b × h (base times height)

Ellipse: A = π × a × b (pi times semi-major axis times semi-minor axis)

Sector: A = ½ × r2 × θ (for angle θ in radians)

Units of Area

  • Metric: Square millimeters (mm2), square centimeters (cm2), square meters (m2), hectares (ha), square kilometers (km2)
  • Imperial: Square inches (in2), square feet (ft2), square yards (yd2), acres, square miles (mi2)
  • Conversion Tip: When converting units, remember to square the conversion factor. For example, 1 m = 100 cm, so 1 m2 = 10,000 cm2

Area Calculation Examples

Example 1: Area of a Rectangle

Given: A rectangle with length 12 meters and width 8 meters

Formula: A = l × w

Calculation: A = 12 m × 8 m = 96 m2

Answer: The area is 96 square meters

Example 2: Area of a Triangle

Given: A triangle with base 10 cm and height 6 cm

Formula: A = ½ × b × h

Calculation: A = ½ × 10 cm × 6 cm = ½ × 60 cm2 = 30 cm2

Answer: The area is 30 square centimeters

Example 3: Area of a Circle

Given: A circle with radius 5 feet

Formula: A = πr2

Calculation: A = π × (5 ft)2 = π × 25 ft2 ≈ 78.54 ft2

Answer: The area is approximately 78.54 square feet

Example 4: Area of a Trapezoid

Given: A trapezoid with parallel sides (bases) of 8 m and 12 m, and height 5 m

Formula: A = ½ × (b1 + b2) × h

Calculation: A = ½ × (8 m + 12 m) × 5 m = ½ × 20 m × 5 m = 50 m2

Answer: The area is 50 square meters

Example 5: Composite Shape

Problem: Find the area of a shape composed of a rectangle (10 × 6 cm) with a semicircle on top (diameter 6 cm)

Rectangle Area: A1 = 10 cm × 6 cm = 60 cm2

Semicircle Area: A2 = ½ × π × (3 cm)2 ≈ 14.14 cm2

Total Area: A = 60 cm2 + 14.14 cm2 ≈ 74.14 cm2

Tips for Calculating Area

Essential Area Calculation Tips

  • Consistent Units: Always ensure all measurements are in the same units before calculating. Convert if necessary
  • Height vs. Side: For triangles and trapezoids, use perpendicular height, not slant height or side length
  • Squared Units: Area is always expressed in square units (cm2, m2, ft2, etc.)
  • Composite Shapes: Break complex shapes into simpler components, calculate each area separately, then add or subtract as needed
  • Circle Measurements: Double-check whether you're given radius or diameter (radius = diameter ÷ 2)
  • Precision: For π calculations, use 3.14159 or your calculator's π button for better accuracy
  • Heron's Formula: When you know all three sides of a triangle but not the height, use Heron's formula: A = √[s(s-a)(s-b)(s-c)] where s = (a+b+c)/2
  • Right Angle Check: For rectangles and parallelograms, verify that angles are actually 90° if assumed

Real-World Applications

Real-World Applications

  • Construction: Calculating flooring, roofing, and wall materials needed for building projects
  • Agriculture: Determining field sizes for planting, fertilizing, and irrigation planning
  • Real Estate: Computing property sizes, lot areas, and living space measurements
  • Interior Design: Measuring rooms for carpeting, painting, and furniture placement
  • Landscaping: Planning lawn areas, garden beds, and patio dimensions
  • Manufacturing: Determining material requirements for cutting, fabric, and sheet metal
  • Urban Planning: Calculating park sizes, building footprints, and land use
  • Art and Design: Computing canvas sizes, poster dimensions, and graphic design layouts

Frequently Asked Questions