A cow is grazing with a rope around its neck and the other end of the rope is tied to a pol. The length of the rope is 10 metres. There are two boundary walls perpendicular to each other, one at a distance of 5 metres to the east of the pole and another at a distance of   metres to the north of the pole. Find the area the cow can graze on.
<p style="text-align: left;">Please give solution with figure.</p>