Class 9 | Chapter 13 | Surface areas and Volumes | Exercise 13.1 | Question 1

Question 1: A plastic box 1.5 m long, 1.25 m wide and 65 cm deep is to be made. It is opened at the top. Ignoring the thickness of the plastic sheet, determine:

(i)  The area of the sheet required for making the box.

(ii)  The cost of sheet for it, if a sheet measuring 1m2 costs Rs. 20.

Prerequisite

Finding surface area of a cube or a cuboid is quite simple. Every cube/cuboid has 6 sides. All we need is find the area of all six sides and add – this will be the total surface area of the cube/cuboid.

A cube is a cuboid that has all edges of equal length. Hence, every cube is a cuboid as well but every cuboid is not a cube. 

It is recommended to understand the core concept of area, surface area and volume before we attempt any question based on these concepts.

 
Derivation of formula – Surface area of cube and cuboid
 

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