How To Read Perimeter of Rectangle Formula


Reading Formulas can make or break how a student comprehends the formula when alone - outside the presence of the teacher, instructor, tutor, or parent.

Formula For Perimeter of Rectangle:  P = 2l + 2w

How To Read:  The Perimeter of a Rectangle is equal to two (2) times the Length of the longer side of the rectangle (L) plus two (2) times the Width of the shorter side of the rectangle (W).

When is reading formulas like this necessary?  At three particular moments, reading this formula in this manner can be effective. 

When students are initially learning what the formula means
When student are learning what it means when they should already know (remediation). 
When students want to remind themselves (basics learning study skill habit)
Remember, Formulas at their introduction are complete statements or thoughts.  Students cannot and will not recall complete thoughts or statements using letters only.  For example, P equals 2 times L plus 2 times W means nothing to the student who would like to connect this formula to a word problem. 

***This minor adjustment will produce significant results and has application across different disciplines that use formulas!!!!!

“Mathematics cannot be learned without being understood - it is not a matter of formulae being committed to memory but of acquiring a capacity for systematic thought.”

- Peter Hilton

Let me know your thoughts.


Does the length of a rectangle need to be the longest side and the width the shortest side? What if the rectangle is also a square?
Good questions!  Typical convention with rectangles is where the length is longer than the width.  So I used typical convention.  The key point here is to distinguish the sides and remain consistent with what l and w references in the formula.  For 2nd question - A rectangle is not also a square.  Why?  A square is a situation where all the sides are the same length.  However, a rectangle and square are both quadrilaterals.  If a rectangle is also a square the different terms would not be math demands increased precision in its descriptions or it will morph into a creative writing class.  Hope this helps.
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