Education Technology

Completing the Square

Published on 10/11/2012

Activity Overview

Complete the square in an algebraic expression.


  • Students will use algebra tiles to build a geometric model of a perfect square quadratic
  • Students will recognize the characteristics in the algebraic expression of a perfect square quadratic
  • Students will complete the square in an algebraic expression
  • Students will relate the patterns for (x + n)2 to (xn)2


  • Perfect square quadratics
  • Coefficient of the x-term
  • Constant term

About the Lesson

Begin the lesson by manipulating algebra tiles to build perfect square quadratics and recording the successful expressions. Continue the lesson by finding the patterns in the algebraic representation of a perfect square quadratic. Next, identify perfect square quadratic expressions and then fill in the missing terms of perfect square quadratics. Finally, apply the patterns they found to perfect square quadratics with a negative coefficient in the x-term.