Notes of chapter: Areas of Parallelograms and Triangles are presented below. Indepth notes along with worksheets and NCERT Solutions for Class 9.
(1) Area of a figure-
Area of a figure is a number (In some units) associated with the part of the plane enclosed by the figure with the following two properties:
(i) If A and B are two congruent figures, then
ar(A) = ar(B)
Area is written in short form as (ar).
In fig above area of figure ABCD is equal to sum of area of figure ABFE and figure CDEF.
ar(ABCD) = ar(ABFE) + ar(CDEF)
(2) Two figures are said to be on the same base and between the same parallels, if they have a common base (side) and the vertices (or the vertex) opposite to the common base of each figure lie on a line parallel to the base.