Question

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

Answer 1

we have
Area of square metal plate $=$ $40$ $\times 40c{m}^2=1600c{m}^2$

Area of each hole $=$ $\pi r^2=\frac{22}{7}\times {\left(\frac{1}{2}\right)}^{2}c{m}^2=\frac{11}{14}c{m}^2$

$\therefore$ Area of $441$ holes $=441$ $\times \frac{11}{14}c{m}^2=346.5c{m}^2$

Hence , Area of the remaining square plate $=(1600-346.5)$ $c{m}^2=1253.5c{m}^2$