Calculating Perimeter and Area

• Perimeter is the total distance around the outside of a two-dimensional shape.
• To calculate the perimeter, add the lengths of all the sides.
• Units for perimeter are always linear, such as centimeters, meters, or kilometers.

Calculating Perimeter for Different Shapes

• Rectangle: Perimeter = 2 × (length + width)
• Square: Perimeter = 4 × side length
• Triangle: Perimeter = side 1 + side 2 + side 3
• Circle (Circumference): Circumference = 2 × π × radius, or Circumference = π × diameter
  • π (pi) is approximately 3.14159

Area

• Area is the amount of space inside a two-dimensional shape.
• Units for area are always expressed as squares, such as square centimeters (cm²), square meters (m²), or square kilometers (km²).

Calculating Area for Different Shapes

• Rectangle: Area = length × width
• Square: Area = side length × side length
• Triangle: Area = ½ × base × height
• Circle: Area =π × radius²
• Parallelogram: Area = base × height
• Trapezium: Area = ½ × (sum of parallel sides) × height

Key Considerations

• For irregular shapes, sometimes it is necessary to divide the shape into simpler shapes, calculate the area of each, and then add the individual areas together.
• Carefully consider the units when calculating and reporting perimeter and area. Ensure consistency – all lengths must use the same unit.
• Accurate measurements are crucial for accurate calculations of both perimeter and area.
• Be precise when labelling units in calculations and answers.
• Understanding geometrical theorems or formulas is essential to solve problems.