# M8.4.15

**relationship between variables is represented in symbols**, numbers can be substituted for all but one of the symbols and the possible value of the remaining symbol computed.

### Finding All Solutions to a Puzzle

The non-zero digits can be organized into a 3-by-3 array such that each row, rneach column, and each diagonal adds up to the same total. How many solutions rnare there? Find and describe them.

### How Big Is the Earth?

In collaboration with another school north or south of yours, rnuse the method of Eratoshenes to determine the circumference rnof the Earth.

### Why Tailgating on Freeways is Unsafe: A Real-life Example Using Quadratic Equations

We discuss how to compute the stopping distance of a car traveling at a given speed-- a real life application of a math topic, quadratic equations, and science topics, such as motion, kinetic energy, and work done. We also discuss the idea that while mathematics can be utilized to model real life situations, there is much more to consider, if one wants more refined and appropriate solutions to real life problems.