Question

A rectangular picture frame is 40 cm by 30 cm. Find its diagonal.​

Answer 1

Difference of two rectangles, one being an external rectangle and the other an internal.

Area of external rectangle = length*breadth = 40cm*30cm = 1200cm square

Area of internal rectangle:

length= 40cm - 2(5cm) = 30 cm

breadth = 30 cm - 2(5cm) = 20 cm

Area = length*breadth = 30cm*20cm = 600 cm square

Area of the border = Area of external rectangle - Area of internal rectangle

= 1200 cm square - 600 cm square

= 600 cm. square

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