Question

A slate is 35 cm long and 20 cm wide. It is surrounded by a wooden frame of width 2.5 cm all around. John coloured the frame, do not consider the thickness of the frame. Find the area of coloured frame.

Answer 1

From the figure, rectangle ABCD

Length$=35cm$

Breadth$=20cm$

Area = length $\times$ breadth

Area = $35\times 20c{m}^2$

Area = $700c{m}^2$

Now, for the wooden frame (rectangle EFGH)

Length$=35+5=40cm$

Breadth$=20+5=25cm$

Area = length $\times$ breadth

Area = $40\times 25$

Area = $1000c{m}^2$

So,3 Area of wooden frame= Area of rectangle EFGH - Area of rectangle ABCD

$=1000-700c{m}^2$

$=300c{m}^2$

Therefore, the area of the wooden frame is $300c{m}^2$