Lotus in the Lake

In a certain lake, swarming with red geese, the tip of a lotus bud was seen to extend a span [half a cubit] above the surface of the water. Forced by the wind, it gradually advanced and was submerged at a distance of two cubits. Compute quickly, mathematician, the depth of the pond.

Līlāvatī, Bhāskara II, 1150

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