ppt on surface area and volume for class 8

1. SURFACE AREA AND
VOLUME
Class -VIII

2. Volume
The capacity of a
three dimensional
object( or a solid
figure) , or the space
occupied by it is
called its volume.
length
b
h
l
l
l

3. Formulas to find volume of a cube
and cuboid
 Volume of a cuboid =length X breadth X height
 Volume of a cube =length X length X length=
(length)3

4. Problems related to volume
 Find the volume of a cube 3.5 m long.
Solution: Given: length=3.5m
To find: Volume of a cube=?
Volume of a cube =(length)3
=(3.5)3
=42.875 m3
Ans: The volume of the cube is 42.875m3

5. contd…
 Find the volume of a cuboid 7.5 cm long,5 cm wide and 4.5cm
high..
Solution: Given: l=7.5cm, b=5 cm and h=4.5 cm
To find: Volume of a cuboid=?
Volume of a cuboid =length X breadth X height
=7.5 X 5 X 4.5
=168.75 cm3
Ans: The volume of the cube is 168.75m3

6. Contd…
 If the volume of a cube is 8m3,find its total surface area and
lateral surface area.
Solution: Given: volume of a cube=8m3
To find: Total surface and lateral surface area of the
cube=?
if Volume of a cube =(length)3
(length)3=8
length=2 m.
Total surface area of cube =6 l2= 6 X 22=24 sq.m
Lateral surface area of cube =4 l2= X 22=16 sq.m

7. Contd…
 A hall is 4.5 m high and the area of the
rectangular shaped floor is 165 sq.m
Find the volume of air in the hall.
Solution : Given: height=4.5 m.
area of rectangular shaped floor =length X breadth=165 sq.m
To find: volume of air in the hall=?
 Volume of a cuboid =length X breadth X

8. Contd..
 An auditorium is 30 m long, 20 m wide and its
ceiling is 20 m above the floor. There are 18
people on stage performing in front of an
audience of 462 people. How much air is there
for each person in the auditorium?
 Hint: volume of room ÷ total no. of people in
the
room

9. Home Assignment
Revision Ex: Q. 6 ,7 ,8 and practice
the sums done in the class.

10. Activity..
1) 1 cm3= ____________ mm3
2) 1 dm3= ____________cm3 =_____
mm3
3) 1 m3= ____________ cm3
4) 1 dcm3= ____________ m3