Question

The area of a square field is 8 hectares. How long would a man take to cross it diagonally by walking at the rate of 4 kmph?

Answer 1

Given

are of square field = 8 hectars

$=8\times 0.01$ (1 hectare = $0.01k{m}^2)$

$=0.08k{m}^2$

Now area of square field = (side of square${)}^2$

$0.08=sid{e}^2$

side = $\sqrt{0.08}$

side $\sqrt{\frac{8}{100}}=\frac{2\sqrt{2}}{10}=\frac{\sqrt{2}}{5}$

Distance covered by man along the diagonal of square field = length of diagonal

$=\sqrt{2}side=\sqrt{2}\times \frac{\sqrt{2}}{5}=\frac{\sqrt{2}}{5}km$

Speed of walking = 4 km/h

$\therefore$ Time taken = $\frac{distance}{speed}$

$=\frac{2}{5\times 4}=\frac{2}{20}=\frac{1}{10}=0.1hr$