Area of a square ground is 4500 sq m, a man crosses 3km of its diagonal in an hour, how much time will he take to cross the whole diagonal .?

First find the side of the square....root 4500 = 67 m ( to nearest m).

Length of diagonal by pythagoras is root 9000 = 95m ( to nearest m)

Travelling at 3km per hour ( which is what I think you meant)

He travels 3000 m in 3600 seconds

1 m in 3600/3000 s

95 m in 3600x 95/3000 = 114 seconds or 1 minute and 54 seconds.

The side of a 4500 m^2 square is 67 m.

The diagonal is sqrt(2*67^2) =~95 m.

If he is walking 3000 m /3600 min. it will take him 1 min 54 sec.

His walk rate is equivalent to taking 3600 secs to walk 3000 m.

Each 5 metres takes 6 secs to walk.

Diagonal D = √(2)s where s is side of square

D^2 = 2s^2 = 9000

D = 30√(10) metres

Time = 36√(10) secs ~ 114 seconds.

Side of square = √4500

Diagonal = √2*√4500 = √9000

= 94.9 m

So it is impossible to walk 3 km along it