Chapter 13: Quadratic Equations

#1011 Windsails - Windsail designer Trevor Baylis develops the shape of a sail on his computer, builds it in his shop and tests it out on the waves.

Ask students if they can think of examples of applications of algebra to sports, and discuss a few answers.  Tell students that algebra and other types of mathematics are used in the design of sports equipment, as in Futures Channel Movie #1011 Windsails.  Watch the movie.

After the movie, sketch a parabola (upward curving, like a smile) on the board, with a quadratic equation written next to it (e.g., y = x² - 6x + 8).  Tell students that just as straight lines lines can be represented by equations, so can curves, and that this particular curve is represented by an equation which has an "x squared" term, call a quadratic equation.

Explain that in this chapter students will learn more about how to work with quadratic equations.