ANS:C - enlarging or reducing plans

Based on the proportional properties of the edges of the similar triangles divided within a four-bar parallelogram linkage is pantagraph. Used to enlarge, reduce and copying drawings. Pantagraph and eidograph are used to enlarge/reduce plan and planimeter is used to measure the area. Pantagraph is a minor instrument used for reproducing the map (whether to enlarge or to reduce). It works on the principle of the parallelogram. It is a minor instrument, and also it is working on the principle if similar triangles, by that way from the basis of similar triangles it will enlarge or reduce the maps.