Surface area and Volume (Part - 5)
1. Ramesh wanted to make a temporary shelter
for her car , by making a box – like structure with tarpaulin that covers all
the four sides and the top of the car ( with the front face as a flap which can
be rolled up ) . Assuming that the stitching margins are very small , and
therefore negligible , how much tarpaulin would be required to make the shelter
of height 2.5 m , with base dimensions 4 m * 4 m ?
Sol. Length of shelter l = 4 m , breadth b =
4 m
and height h = 2.5 m
Area of four walls and top of shelter = Total
area of shelter – area of floor
Area of four walls and top of shelter = 2 ( l
b + b h + h l ) – l b
Area of four walls and top of shelter = 2 ( 4
* 4 + 4 * 2.5 + 2.5 * 4 ) – 4 * 4 m^2
Area of four walls and top of shelter = 2 (
16 + 10 + 10 ) – 16 m^2
Area of four walls and top of shelter = 2 (
36 ) – 16 m^2
Area of four walls and top of shelter = 72 -
16 m^2
Area of four walls and top of shelter = 56
m^2
Hence , 56 m^2 tarpaulin is required to make
this shelter .
2. Ramesh wanted to make a temporary shelter
for her car , by making a box – like structure with tarpaulin that covers all
the four sides and the top of the car ( with the front face as a flap which can
be rolled up ) . Assuming that the stitching margins are very small , and
therefore negligible , how much tarpaulin would be required to make the shelter
of height 2.5 m , with base dimensions 3 m * 3 m ?
Sol. Length of shelter l = 3 m , breadth b =
3 m
and height h = 2.5 m
Area of four walls and top of shelter = Total
area of shelter – area of floor
Area of four walls and top of shelter = 2 ( l
b + b h + h l ) – l b
Area of four walls and top of shelter = 2 ( 3
* 3 + 3 * 2.5 + 2.5 * 3 ) – 3 * 3 m^2
Area of four walls and top of shelter = 2 ( 9
+ 7.5 + 7.5 ) – 9 m^2
Area of four walls and top of shelter = 2 (
24 ) – 9 m^2
Area of four walls and top of shelter = 48 -
9 m^2
Area of four walls and top of shelter = 39
m^2
Hence , 39 m^2 tarpaulin is required to make
this shelter .
maths ncert solutions |
3. Ramesh wanted to make a temporary shelter
for her car , by making a box – like structure with tarpaulin that covers all
the four sides and the top of the car ( with the front face as a flap which can
be rolled up ) . Assuming that the stitching margins are very small , and
therefore negligible , how much tarpaulin would be required to make the shelter
of height 2 m , with base dimensions 4 m * 3 m ?
Sol. Length of shelter l = 4 m , breadth b =
3 m
and height h = 2 m
Area of four walls and top of shelter = Total
area of shelter – area of floor
Area of four walls and top of shelter = 2 ( l
b + b h + h l ) – l b
Area of four walls and top of shelter = 2 ( 4
* 3 + 3 * 2 + 2 * 4 ) – 4 * 3 m^2
Area of four walls and top of shelter = 2 (
12 + 6 + 8 ) – 12 m^2
Area of four walls and top of shelter = 2 (
26 ) – 12 m^2
Area of four walls and top of shelter = 52 -
12 m^2
Area of four walls and top of shelter = 40
m^2
Hence , 40 m^2 tarpaulin is required to make
this shelter .
4. Ramesh wanted to make a temporary shelter
for her car , by making a box – like structure with tarpaulin that covers all
the four sides and the top of the car ( with the front face as a flap which can
be rolled up ) . Assuming that the stitching margins are very small , and
therefore negligible , how much tarpaulin would be required to make the shelter
of height 1.5 m , with base dimensions 4 m * 3 m ?
Sol. Length of shelter l = 4 m , breadth b =
3 m
and height h = 1.5 m
Area of four walls and top of shelter = Total
area of shelter – area of floor
Area of four walls and top of shelter = 2 ( l
b + b h + h l ) – l b
Area of four walls and top of shelter = 2 ( 4
* 3 + 3 * 1.5 + 1.5 * 4 ) – 4 * 3 m^2
Area of four walls and top of shelter = 2 (
12 + 4.5 + 6 ) – 12 m^2
Area of four walls and top of shelter = 2 (
22.5 ) – 12 m^2
Area of four walls and top of shelter = 45 -
12 m^2
Area of four walls and top of shelter = 33
m^2
Hence , 33 m^2 tarpaulin is required to make
this shelter .
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