Question

A drain cover is made from a square metal piece of side 40 cm having 441 holes of diameter 1 cm each drilled in it. find the area of remaining square plate

Answer 1

First, we find area of square =40 x 40=1600 cm

Then, we find area of hole=(22/7)x0.5x0.5=0.785

No. of Holes=441

Therefore, total area of holes=346.185 cm

Hence, area left=1600-346.185=1253.815

Answer 2

Answer:

Step-by-step explanation:

Area of square metal plate = 40 ×40cm

2

=1600cm

2

Area of each hole = πr

2

=

7

22

​

×(

2

1

​

)

2

cm

2

=

14

11

​

cm

2

∴ Area of 441 holes =441 ×

14

11

​

cm

2

=346.5cm

2

Hence , Area of the remaining square plate =(1600−346.5) cm

2

=1253.5cm

2