Areas of Parallelograms and Triangles

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).

 

Eg:-

Area of a figure of NCERT Chapter Areas of Parallelograms and Triangles

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.

 

Eg:-

(i)

Diagram on the same base and between the same parallels

(ii)

(iii)

(iv)

(v)

Parallelograms on the same base and between the same parallels are explainedParallelograms on the same base and between the same parallels Triangles on the same base and between the same parallels are explained

Helping Topics

NCERT Solutions Class 9

Worksheet Class 9

Mensuration

 

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