20cm long cylinderical pencils of diameter 1cm each are packed in a cuboidal box in two rows . If there are 20 pencils to be arranged in this box, then what is the surface area of this box?
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Dimensions of the cyliderical pencil is,
Diameter = d = 1 cm
Length of the pencil = 20 cm
Given 20 pencils are arranged in a cubiodal box
in two rows,
Now dimensions of the cuboidal box is
Lenth = l = each pencil length = 20 cm
breadth = b = 10 × each pencil diameter = 10 × 1cm = 10cm
Height = h = 2 × each pencil diameter = 2 × 1 cm = 2 cm
Total surface area of the box = 2 ( lb + bh + lh )
= 2 ( 20 × 10 + 10 × 2 + 20 × 2 )
= 2 ( 200 + 20 + 40 )
= 2 × 260
= 520 square cm.
Answered by
1
the pencil are 20 cm long which means the lenght of the box= 20cm
as given
they are arranged in two rows and there are 20 pnecil so
pencil in one row=20/2=10pencil
if one pencil have a diameter of 1cm then,
daimeter of 10 pencils= breath of the box
1×10= 10 cm
the breath of the box is 10cm
now,
the height of the box will be equal to sum of the daimeter of 2 pencil as they are arranged in a parallel way
h of box = 2cm
LSA of cuboid=2(LB)h
=2(10•20)2
=120cm^2
TSA OF CUBOID=2(LB+BH+HL)
2(20•10+10•2+20•2)
520sqcm
as given
they are arranged in two rows and there are 20 pnecil so
pencil in one row=20/2=10pencil
if one pencil have a diameter of 1cm then,
daimeter of 10 pencils= breath of the box
1×10= 10 cm
the breath of the box is 10cm
now,
the height of the box will be equal to sum of the daimeter of 2 pencil as they are arranged in a parallel way
h of box = 2cm
LSA of cuboid=2(LB)h
=2(10•20)2
=120cm^2
TSA OF CUBOID=2(LB+BH+HL)
2(20•10+10•2+20•2)
520sqcm
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