Units of Measurement and Perimeter

Units of Measurement

• Length is a one-dimensional measurement of part of an object.

• Distance is the space between objects.

• The standard unit of length/distance in the Metric system is the metre.

• Other common units include kilometre, centimetre, and millimetre.

  • millimetre (mm)
  • centimetre (cm)
  • metre (m)
  • kilometre (km)

• Mass

  • gram (g)
  • kilogram (kg)
  • tonne (t)

• Volume/Capacity

  • millilitre (ml)
  • centilitre (cl)
  • litre (l)

Perimeter

• Perimeter (P) is the distance around the outside of a two-dimensional, closed shape.
• Units must be the same when calculating perimeter.
• Sides with the same markings (dashes) are equal in length. These markings are called tick marks or hatch marks.

Composite Shapes

• A composite (or compound) shape is made of two or more basic shapes.
• It can be broken down into these basic shapes to make calculations easier.

Calculating Circle Measurements

• A circle represents points the same distance from a center point.
• Radius: Length from the center to the edge.
• Diameter: Distance across the center of the circle.
• Circumference: The circle's perimeter.
• Pi (π): A non-repeating decimal that relates diameter and circumference . Common approximations include: 3.14159 (to 5 decimal places) or 3.14 (to 2 decimal places) or 22/7.

Area

• Area describes the number of unit squares that fit inside a shape.
• Area can be calculated using formulas based on the shape's measurements.
  • Centimetres: Area in cm²
  • Metres: Area in m²
  • Millimetres: Area in mm²

Basic Shapes

• Rectangles, parallelograms, and triangles can all have area calculated using two perpendicular dimensions.
• Rectangle: Area = Length x Width
• Parallelogram: Area = base x height
• Triangles: Area = (base x height)/2

3D Shapes (Solids)

• Three-dimensional shapes (3D shapes) are solids.
• They have length, width/depth, and height.

Pyramids

• Pyramids have triangular sides that meet at a vertex.
• The shape of the base gives the pyramid its name.

Prisms

• Prisms have rectangular sides, and the shape is the same throughout.
• Drawing 3D shapes can be done using isometric paper or grid paper.
• 2D representations of different views (side, front, top) can show the solid.
• A net is a complete 2D representation of the shape, showing all faces laid flat.

Volume

• Volume describes the amount of space a 3D shape occupies.
• Rectangular prism/cuboid: Volume = Length x Width x Height
• Triangular prism: Volume = (Area of triangular base x depth)
• Area of a triangle: Area = (base x height)/2