the length breadth and height of a room are 5m,4m and 3m respectively Find the cost of whitewashing the wall of room and celling at the rate of Rs.7.50 per sq.m.
Answers
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The cost of white washing of four walls
and ceiling of room = ₹ 555
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Explanation-:
Surface Area of cuboid-:
“SA = 2 ( b h + hl + l b)”
Area of base of cuboid-:
“A = l x b”
A = Area
l = length
B = breadth
H = height
SA = Surface Area
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Given ,
Length of room -: 5 m
Breadth of room -: 4 m
Height of the room -: 3 m
The cost of white washing is at the rate
of ₹7.50 per sq. m.
To find ,
The cost of white washing the four wall of
room and ceiling.
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We have to white wash the four walls
and ceiling of the room.
Area to be white washed -:
Surface area of cuboid - Area of base
Surface Area of cuboid-:
“SA = 2 ( b h + hl + l b)”
Area of base of cuboid-:
“A = l x b”
Now ,
Area to be white washed -:
2 ( b h + h l + l b) - l b
Length of room -: 5 m = l
Breadth of room -: 4 m = b
Height of the room -: 3 m = h
Then ,
= 2 ( b h + h l + l b ) - l b
= 2 ( (4 x 3 ) + ( 3 x 5) + (5 x 4) ) - (5 x 4)
= 2 (4 x 3) + 2 ( 3 x 5) + 2 (5 x 4) - (5 x 4)
= 2 ( 4 x 3) + 2 (3 x 5) + 2( 20 ) - 20
= 2 ( 4 x 3) + 2 (3 x 5) + 40 - 20
= 2 ( 4 x 3) + 2 (3 x 5) + 20
= 2(12) + 2 (15) + 20
= 24 + 30 + 20
= 74 m ^2
Now ,
Area need to be white washed -:74 m ^2
Then ,
Cost of white washing = ₹7.50 per
sq. m^2
Cost of white washing of four walls of
room and ceiling of room -:
• Area of four walls and ceiling of room x
Cost of white washing
Area of four walls and ceiling of room -:
74 m^2
Cost of white washing-: ₹7.50 per sq. m
Then ,
= 74 x 7.50
= ₹ 555
Hence ,
• The cost of white washing of four walls
and ceiling of room = ₹ 555
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Cuboid-: A cuboid is a three dimensional
having six faces, eight vertices and
twelve edges.
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