THE MATRYOSHKA DOLL

For generations, special wooden nesting dolls called matryoska have been handcrafted in Russia. This type of cylindrical doll opens at the midsection and nested inside is a smaller wooden doll (with the same shape) which itself opens to another doll. Some matryoshka are made up of ten or more dolls! The smallest doll, often less than a centimeter tall, is solid wood.

Explain why, under ideal conditions, the sum of the volumes of the nested wooden shells of the different-sized dolls will calculate the full volume of the interior of the largest doll.