Answer:The answer, the displacement is 10√2 m

Explanation:

Look, let's note all the given info,

SIDE of the field = 10m

Time taken to walk along the boundary of the square field = 40s

Time given to calculate the displacement = 2 min 20 s= 2×60 + 20

=140s

Total distance walked by him in 140s =

40s=> 40m

140s => 'x'

Therefore, x = 140×40/40= 140 m

That means, distance covered by him in time 2 min 20s = 140m

Perimeter of the field = 10×4 = 40 m

No. Of ROUNDS taken = 140/40 = 4.5

That means, he didn't complete the 4th time.

Now IMAGINE, make a right angled triangle, from the point the FARMER started to the point where he ENDED ine the second side. Look at the diagram, attached here.

So, it's a right angled triangle,

By Pythagoras theorem,

(Side) ^2 = √(10) ^2 +(10) ^2

Side2 = √100 + 100=√200

Side = 10√2m ..... ( taking square root of both sides)

{ here side means side of a right angled triangle}

Displacement = final - initial position

= 10√2-0= 10√2m

Hope it helps.... :)

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