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
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.