Question

A drain cover is made from a square metal plate of side 40 cm and has 336 holes of radius 1 cm each drilled in it. Find the area in ${\text{cm}}^2$ of the remaining square plate.
(Take $\pi$ =$\frac{22}{7}$)

• A. 253
• B. 544
• C. 636
• D. 564

Answer 1

The correct option is B

544

Area of a square plate
$={\text{side}}^2$

Given length of the side of the square plate = 40 cm
Area of square plate
$={40}^2$
$=1600c{m}^2$

Area of a circle
$=\pi r^2$
There are 336 holes of radius 1 cm each.

Total area of circles
$=336\times \frac{22}{7}\times 1^2$
$=1056c{m}^2$

Remaining area = [Area of square plate- Total area of circles]
$=1600-1056$
$=544c{m}^2$

$\therefore$ Area of remaining square plate
$=544c{m}^2$