Heron's Formula of Class 9
The branch of mathematics that deals with measurement especially the derivation and use of algebraic formulae to measure the areas ,surface area , volumes and different parameters of geometric figure.
The perimeter of a plane figure is the length of its boundary. In case of a triangle or a polygon, the perimeter is the sum of the lengths of its sides.
A dimension is a direction in which one can measure distance. For example, “horizontal distance and vertical distance ” or “left and right” is a dimension.
Length is the size in one dimension.It could be the amount of string needed to cover a line.
Area is the size in two dimensions.It could be the amount of paper needed to cover a shape.
Units of Perimeter :
The unit of perimeter is the same as the unit of length i.e. centimetre (cm), metre(m), kilometere (k m) etc.
1 centimetre (cm) = 10 milimetre (mm)
1 decimetre (dm) = 10 centrimetre
1 metre (m) = 10 decimetre
= 100 centimetre
= 1000 milimetre
1 decamete (dam) = 10 metre
= 1000 centimetre
1 hectometre (hm) = 10 decametre
= 100 metre
1 kilometre (km) = 1000 metre
= 100 decametre
= 10 hectometre