For this assignment, I went about this question kind of as if the shape was a cone because it made the most sense in my mind for the ‘base’ to be the lake surface area and the bottom of the lake to be the rest of the cone, since the ground most likely caves in because of the mountains.  I converted all the measurements first into metres, then into litres so that the conversion would be easier. This way the weight is also a lot easier to find (1L of water=1kg)