2. A suitcase with measures 80 cm x 48 cm x 24 cm is to be covered with a tarpaulin cloth. How many meters of tarpaulin of width 96 cm is required to cover 100 such suitcases?
The lateral surface area of a hollow cylinder is 4224cm2. It is cut along its height and formed a rectangular sheet of width 33 cm. Find the perimeter of rectangular sheet?
Answers
Answer:
q1
Length of suitcase box, l = 80 cm,
Breadth of suitcase box, b= 48 cm
And Height of cuboidal box , h = 24 cm
Total surface area of suitcase box = 2(lb+bh+hl)
= 2(80×48+48×24+24×80)
= 2 (3840+1152+1920)
= 2×6912
= 13824
Total surface area of suitcase box is 13824 cm2
Area of Tarpaulin cloth = Surface area of suitcase
l×b = 13824
l ×96 = 13824
l = 144
Required tarpaulin for 100 suitcases = 144×100 = 14400 cm = 144 m
Hence tarpaulin cloth required to cover 100 suitcases is 144 m.
q2
Lateral surface area of hollow cylinder = 4224 cm2
Height of hollow cylinder, h = 33 cm and say r be the radius of the hollow cylinder
Curved surface area of hollow cylinder = 2πrh
4224 = 2×π×r×33
r = (4224)/(2π×33)
r = 64/π
Now, Length of rectangular sheet, l = 2πr
l = 2 π×(64/π) = 128 (using value of r)
So the length of the rectangular sheet is 128 cm.
Also, Perimeter of rectangular sheet = 2(l+b)
= 2(128+33)
= 322
The perimeter of rectangular sheet is 322 cm.
more information about mensuration chapter class 8
Area of Trapezium :- height x (sum of parallel sides)/2
Area of Rhombus :- ½ x d1 x d2
Area of Special Quadrilateral :- ½ x d x (h1 + h2)
Surface area of Cuboid :- 2(lb x bh x hl)
Surface area of Cube :- 6a2
Surface area of cylinder :- 2πr(r + h)
Volume of Cuboid :- l × b × h
Volume of Cube :- a3
Volume of cylinder :_ πr2h