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Any mathematicians out there??

(58 Posts)
Mogsmaw Mon 17-Mar-25 11:20:51

I remember this from school. The maths teacher concluded it was a problem for advanced mathematics and not something we could solve at school. I suspected then, as I do now, that he hadn’t the skills to solve it!

Elegran Mon 17-Mar-25 11:19:12

Now I have finished my coffee, I can see that my equation only gives you an area covered by a circle nearest the post which is clearly not as big as the area of the rest of the round field outside that circle.

I give up.

Elegran Mon 17-Mar-25 11:16:11

I'll send this puzzle to MY brother. He doesn't have enough to keep his brain exercised since he retired.

Elegran Mon 17-Mar-25 11:14:19

No, I forgot to substitute the length of the rope (L) for (R) into the standard equation for finding the area of the circle.

Should be B = the square root of ( ( 3.14 x L ) divided by 2)
Or maybe not.

Calendargirl Mon 17-Mar-25 11:12:40

Life’s too short!

Elegran Mon 17-Mar-25 11:11:39

I am not a mathematician, and would build a wall across the circle, going through the exact centre, and confine the cow in one half. However, the logic of the question goes something like this:-

The length of the rope (L) is the radius of the circle.
The area (A) of a circle is Pi R squared.
So half the area (B) of the circle is Pi R squared divided by 2.
What you need to find is B.

B = the square root of ( ( 3.14 x R ) divided by 2)

But maybe not.

Shelflife Mon 17-Mar-25 10:52:09

Sorry, way beyond me! Hope someone solves this for you - there are some very clever people on GN !

Katek Mon 17-Mar-25 10:28:40

My brother and I were chatting yesterday and the following came up in our conversation. Neither of us could remember formula so short of drawing it on graph paper and counting each little square we're stumped.

A farmer's cow is tied to a rope staked on the edge of a circular field of grass. He wants the cow to eat exactly half the grass in the field. What is the equation that computes the length of the rope (x) so that the cow eats exactly half grass?

My grey cells are a bit sluggish - it is a Monday morning! Anybody more alert?grin