Students will learn how to solve quadratics by taking the square root of both sides. For example, solve \(x^2 - 9 = 0.\) As a more interesting problem, find all the real roots for this difference of squares: \(9x^4 - 25x^2 = 0\) (video.) As an application of this skill, students will learn how to find the radius or diameter of a circle given its area (video). As another example problem, consider a right triangle having a hypotenuse of length 10, one leg of length 5, and the other leg unknown. The unknown length can be found by solving a quadratic equation, which is eventually solved by taking the square root of both sides. Conclude by giving your students this challenge, which requires knowing the product of powers rule for exponents, and knowing that you can take the square root of boths sides of an equation.