# RD Sharma Solutions Class 7 Mathematics Solutions for Mensuration 1 Exercise 20.2 in Chapter 20 - Mensuration 1

Question 5 Mensuration 1 Exercise 20.2

A painting 8 cm long and 5 cm wide is painted on a cardboard such that there is a margin of 1.5 cm along each of its sides. Find the total area of the margin.

Given length of cardboard including margin = 8 cm

Breadth of the cardboard including margin = 5 cm

Area of the cardboard including the margin = 8 cm x 5 cm = 40 cm^2

From the figure, we can observed that,

New length of the painting without margin = 8 cm – (1.5 cm + 1.5 cm)

= (8 – 3) cm

= 5 cm

New breadth of the painting without margin = 5 cm – (1.5 cm + 1.5 cm)

= (5 – 3) cm

= 2 cm

Area of the painting not including the margin = 5 cm x 2 cm = 10 cm^2

Hence, Area of the margin = Area of the cardboard including the margin – Area of the painting

= (40 – 10) cm^2

= 30 cm^2

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