The document discusses different types of 2D and 3D shapes. It defines rectangles, squares, triangles, and hexagons as plane or 2D figures. Cuboids, cubes, and cylinders are defined as solid or 3D figures. Solid figures are made up of plane surfaces or figures. The surface area of solids is calculated by finding the total area of these plane figures. Formulas are provided to calculate the surface area of cuboids and cubes. Practice questions are included for students to calculate surface areas of shapes based on given measurements.

1. PowerPoint presentation

2. What it is

3. it is rectangle

4. What it is

5. it is square

6. What it is

7. it is triangle

8. What it is

9. it is hexagon

10. Which type of figures these
are
•

11. These are plane figures
or 2 dimensional figures
•

12. What it is

13. it is cuboid

14. What it is

15. it is cube

16. What it is

17. it is cylinder

18. Which type of figures these
are
•

19. These are called solid figures
or 3d figures
•

20. • HOW THESE SOLID FIGURE ARE
MADE UP OF

21. • THESE SOLID FIGURES ARE MADE UP OF
PLANE SURFACES OR PLANE FIGURES

22. Side 2
Bottom
Back
Top
Side 1
Front
Side 2
Bottom
Back
Top
Side 1
Front
Length (L)
Breadth (B)
Height (H)
Cuboid

23. • WHEN WE TAKE THE AREA OF THESE
PLANE FIGURES AS A SUM , THEN IT IS
CALLED THE SURFACE AREA OF THE SOLID
FIGURES.

24. • NOW LET US DISCUSS THAT HOW TO FIND
THE SURFACE AREAS OF CUBOID

25. The net
L
L
L
L
B
H
H
H
H
L
B
B B BB
H
H

26. H
B
L
H
B
H
L
L
L
H
B
L
H
B
H
L
L
Total surface Area

27. • Total surface Area = L x H + B x H + L x H +
B x H + L x B + L x B
• = 2 (LxB) + 2(BxH) + 2(LxH)
• = 2 ( LB + BH + LH )

28. • NOW LET US DISCUSS ABOUT THE
SURFACE AREA OF CUBE

29. WHAT IS THE DIFFERENCE
BETWEEN
A CUBOID AND A CUBE

30. THE NET FOR THE CUBE

31. Cube
L
L
L
• Total surface area = 2(LxL) + 2(LxL) + 2(LxL)
= 6L2

32. AREA OF FOUR WALLS
. THIS IS ACTUALLY THE AREAS OF THE
SURFACES WHERE THE HEIGHT IS INVOLVED
. THIS AREA IS ALSO CALLED THE LATERAL SURFACE
AREA
• IN CASE OF CYLINDER THIS PART IS CALLED
THE CURVED SURFACE AREA BECAUSE THIS PART IS
CURVED IN CASE OF CYLINDER

33. • LSA OF CUBOID=2(L*H) +2(B*H)
= 2(L+B)H
LSA OF CUBE =L2 + L2 + L2 + L2
= 4 L2

34. PRACTICE QUESTION
1. FIND THE SURFACE AREA OF CUBOIDAL BOX HAVING THE ME
ASUREMENT 10cm X 5cm X2cm.

35. SOLUTION
S A OF CUBOID = 2(LB+BH+HL)
= 2(10*5 + 5*2 + 2*10)
= 2(50+10+20)
= 2*80
=160 CM2.

36. PRACTICE QUESTION
2 FIND THE SIDES OF A CUBE WHOSE SURFACE
AREA IS 600 CM2.

37. SOLUTION
S A OF CUBE = 6a2
600cm2= 6 a2
100 cm2= a 2
TAKING SQUARE ROOT BOTH SIDE
10 cm = a
EACH SIDE = 10cm.

38. LEARNING ACHIEVEMENT TEST
1. APLASTIC BOX 1.5 cm LONG 1.25 cm WIDE AND 65 cm IS TO BE MADE.
IT IS OPENED AT THE TOP. IGNORING THE THICKNESS OF THE PLASTIC
SHEET, DETERMINE :
(A) THE AREA OF THE SHEET REQUIRED FOR MAKING THE BOX
(B) THE COST OF THE SHEET FOR IT, IF A SHEET MEASURING 1m2 COSTS
Rs 20.
2. THE LENGTH , BREADTH AND HEIGHT OF A ROOM ARE 5m, 4m AND 3m
RESPECTIVELY. FIND THE COST OF WHITEWASHING THE WALLS OF T
HE ROOM AND THE COST OF CEILING AT THE RATE OF Rs 7.50 PER m2.
3. THE FLOOR OF A RECTANGULAR HALL HAS A PERIMETER 250m. IF THE
COST OF PAINTING THE FOUR WALL AT THE RATE OF Rs 10 PER m2 IS Rs
15000, FIND THE HEIGHT OF THE HALL.

39. Home Assignment
• DISCUSS
ABOUT THE DIAGONALS OF
CUBOID AND CUBE

40. THANK YOU