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 km per hours ?

Answer 1

Given, the area of square field = 8 hectares

= 8 × 0.01 [ 1 hectare = 0.01 $k{m}^2$]

= 0.08 $k{m}^2$

Now, the area of square field = $(side{)}^2$ = 0.08

$side=\sqrt{0.08}=\sqrt{\frac{8}{100}}=\frac{2\sqrt{2}}{10}=\frac{\sqrt{2}}{5}km$

Distance covered by the man along the diagonal of square field = length of diagonal $=\sqrt{2}\times side=\sqrt{2}\times \frac{\sqrt{2}}{5}=\frac{2}{5}km$

Speed of walking = 4 km/h.

$Timetaken=\frac{Distance}{Speed}=\frac{2}{5\times 4}=\frac{2}{20}=\frac{1}{10}=0.1hour=\frac{1}{10}\times 60minutes=6minutes$