If you visit or live in Japan, you may have seen a watermelon shaped like the one above. Yes, there are watermelons that are rectangular prisms. These watermelons aren't the work of genetic engineers. (Although genetic engineers are probably working on creating their own vegetables and fruits in the shape of a rectangular prisms). They are made by regular farmers growing watermelons inside a clear rectangular prism. The rectangular prisms have a volume that is nearly the same as the final volume of normal-sized watermelon. As the watermelon grows, it slowly fills up the container, taking the shape of the rectangular prism.

This is a time-consuming and labor-intensive process. "Time-consuming" and "labor-intensive" always translates to "expensive." Here is a picture of a $300 dollar cube watermelon in a Japanese grocery store.

That's a lot to pay for a watermelon! But there are definitely advantages to having fruits and vegetables shaped like rectangular prisms. Click on the images below to learn about some of these advantages.

Yes, objects that are shaped like rectangular prisms have a lot of advantages. We see so many of them every day. That's why we are going to take time to give some special attention to these common but very important three-dimensional shapes. In this lesson, we are going to get to know rectangular prisms and how to calculate their volumes.