Area of a triangle

and parallelogram

STANDARD : 7TH

• The area of any shape is a measure of the 2 dimensional

space that it covers.

• Area is measured in squares – e.g. square cm, square meters

and square km.

What is the area

of this parallelogram?

W=width

L=length H=height

What is the area

of this parallelogram?

CUT HERE

W=width

L=length H=height

PARALLELOGRAM

What is the area

of this parallelogram?

Move and paste Here

B= base

H=height

This Is ( like) a rectangle obtained from Parallelogram

Area of Rectangle = Area of parallelogram

Area of Rectangle= Base x Height

(perpendicular height H)

B= base

H=height

L=length

B = base

H=height

Area of Parallelogram= Base x Height

Find the area of parallelogram whose base is 30 cm and

height is 20cm

A

B

D

CE

20 cm

30 cmA ( )ABCD = l ( BC ) × l ( AE )

= 30cm× 20cm

= 600 sq cm

Suppose ABCD is a parallelogram

Given : l ( BC ) = 30 cm , l ( AE ) = 20 cm

To find out : A ( )ABCD

Solution :

The area of parallelogram is 600 sq cm

If the area of parallelogram is 250 sq cm and its height is

25 cm , what is the length of its base.

Suppose DEFG is a parallelogram

Given : l ( DH ) = 25 cm , A ( DEFG ) = 250 sq cm

To find out : l ( EF ) =?

SOLUTION :

Area of Parallelogram= Base x Height

A ( DEFG ) = l ( EF ) × l ( DH)

250 cmxcm = l ( EF) x 25 cm

250 Xcm Xcm = l ( EF)

25 xcm

10 cm = l ( EF)

The length of its base is 10 cm

D

E F

G

H

EVALUATIVE QUESTIONS

Evaluation:

The area of parallelogram ABCD is 300 sqcm . The length of its base

is 15 cm what will be the height of parallelogram.

If the length of base of parallelogram is 15 cm and its height is 30 cm.

find o the area of parallelogram.

The area of parallelogram ABCD is 450 sqcm . The length of its

height is 9 cm what will be the base of parallelogram.

COPY THIS

W=width

L=length H=height

What is the area of this triangle?

PASTE HERE

H=height

W=width

L=length

cho

H=heightL=length

W=width

FLIP HORIZONTALLY!

H=heightL=length

B = Base

INVERT HERE

Area of triangle= ½ (Base x Height)

The area of the

triangle is ½ the

area of this

parallelogram

10cm

8cm

6cm

7cm

Area of triangle =½ base X height

= ½ x 10 cm x 8cm

= ½ x 80 sq cm

=40 sq cm

Area of triangle =½ base X height

= ½ x 6cm x 7cm

= ½x42sqcm

=21 sq cm

EXAMPLES

J

k L M

The length of height of triangle is 9m

If the area of triangle is 90 sq m and its base

is 20 m , what is the length of its height.

Suppose JKM is a triangle

Given : A( JKM ) = 90 sq m , l ( KM ) = 20 m

To find out : l ( JL )

Solution :

Area of triangle =½ X base X height

90sqm = ½ X l ( KM )X l(JL)

90sqm = ½ X 20 m X l (JL)

90sqm = 10m X l (JL)

9m = l (JL)

The area of triangle GEF is 100 sqcm . The length of its

base is 25 cm. what will be the height of triangle.

If the length of base of triangle is 12 cm and its height is

27 cm. find out the area of triangle.

The area of triangle RPS is 120 sqcm . The length of its

height is 5 cm what will be the base of triangle.