(RF/Length to be measured)

(Length to be measured/RF)

RF x length to be measured

RF x length of scale required

Drawing smaller than object

Drawing smaller, object bigger

Drawing bigger, object smaller

Drawing smaller, object smaller

Plain scale

Vernier scale

Scale of chords

Comparative scales

Plain scale

Vernier scale

Diagonal scale

Comparative scale

Size of scale

Size in drawing

Size of the object

Size of object and drawing