Types of Graphical Scale :-

• Plain Scale
• Diagonal Scale
• Vernier Scale
• Comparative scale
• Scale of chords

Representative fraction (R.F.) :-

When a 1 cm long line in a drawing represents 1 meter length of the object

Length of scale  = RF x Maximum distance to be represented

Plain scale :-

• A plain scale is  used to indicate the distance in a unit and its nest subdivision.
• A plain scale consists of a line divided into suitable number of equal units. The first unit is subdivided into smaller parts.
• The zero should be placed at the end of the 1st main unit.
• From the zero mark, the units should be numbered to the right and the sub-divisions to the left.
• The units and the subdivisions should be labeled clearly.
• The R.F. should be mentioned below the scale.