"Question 1 There are two cuboidal boxes as shown in the adjoining figure. Which box requires the lesser amount of material to make?
Class 8 Mensuration Page 186"
Answers
Mensuration:
Mensuration is the branch of mathematics which concerns itself with the measurement of Lengths, areas & volume of different geometrical shapes or figures.
Surface area:
The surface area of a solid is the sum of the areas of the plane or curved faces of the solid.
It is measured in square units such as square centimetre (cm²) and square metre (m²).
Surface area of cuboid or cube is the sum of the surface areas of its six rectangular faces.
Surface Area of Cuboid is =
2(lb + lh + bh)
By surface area of a cuboid or cube we mean the total surface area.
Total surface area of a cube= 6a²
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Solution:
Given:
Length of cuboidal box(l) = 60 cm
Breadth of cuboidal box (b) = 40 cm
Height of cuboidal box(h)= 50 cm
Total surface area of cuboidal box= 2(lb+bh+hl)
= 2 (60 × 40 + 40 × 50 + 50× 60)
= 2 (2400 + 2000 + 3000)
= 2 × 7400
= 14800 cm²
Total surface area of cuboidal box= 14800 cm²
(b) Given:
Side of a cube (a) = 50
Total surface area of a cube= 6a²
Total surface area of a cube=6× (50)²
= 6 × 2500
= 1500 m²
Total surface area of a cube=1500 m²
Hence cuboidal box (a) requires the lesser amount of material to make.
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Hope this will help you..
