one way of restating Archimedes' Principle is that the mass of a block that is floating in a fluid is equal to the mass of the fluid displaced by the block. Imagine that we have a solid block in which all sides are 1 cm long a cube with a volume of 1 cm^3. we set it in a beaker of pure water and find that, when the block and water come to rest, 70% of the block is submerged under water, so a=7 cm and b=10cm