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vaibhav101
- Master | Next Rank: 500 Posts
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Hello.
First of all, the following solution will give us the least length of the rope that allows the horse to graze over an area of 1100m^2. Second, I am going to assume that the rope will be tied to a stick in the center of a field, that is to say, the area in which the horse will graze will be a circle, whose radius is the length of the rope.
We want that the area of the circle mentioned will be greater than 1100m^2, this implies that we want to find r such that $$\pi\cdot r^2>1100 \ m^2\ \ \ \ \Rightarrow\ \ \ r>18.7\ m \ .$$ Hence, the length of the rope must be greater than 18.7 m.
According to the given options (and my assumption about the least length), the correct answer is the option A.
I really hope it helps.
