Solution Step 0/0
If a bottle, partly filled with liquid, has a round, square, or rectangular bottom which is flat, it is possible to find its volume using only a ruler. What would be a critical condition?
Explanations
The area of a circle, square, or rectangle can easily be calculated after measuring sides or diameter with a ruler. Call the area S.With the bottle upright (left diagram), measure the height h1 of the liquid. The full part of the bottle has the volume S x h1.
Turn the bottle upside down and measure the height h2 of the air space (right diagram). The empty part of the bottle has the volume S x h2. The whole bottle has the volume S x (h1 + h2).
[After Boris A. Kordemsky. The Moscow Puzzles: 359 mathematical recreations. 1972]
Check Liquid's color
Check Upside-down
Check The 2nd bottle
Check A watch used
