A farmer owns a circular field, the diameter of which is 100 feet.

The farmer also owns a goat as well as a length of rope.

There's a post on the periphery of the field.

The farmer wants to tether the goat to the post (using the rope, of course) so the goat can graze precisely half of the field.

From the post to the goat, how long should the rope be?

General note: the farmer's neighbors don't care if the goat grazes outside of the farmers property. The only requirement is to get half of the farmer's field grazed.

Note to lawyers: the intent of the problem requires you to disregard the length of the goat's neck, muzzle, and any other bodily parts.==============================

Doesn't really matter since the goat will eat through the rope.