Reflection: Connection to Prior Knowledge Finding the Area of a Rectangle - Section 4: Roundtable

Question 7 was a little challenging for my students.  The students have to find the length of a side given the area and the width.  I had a proud teacher-mom moment when one of my students came to the board to explain how he solved this problem.

He said...

I know that the area formula for a rectangle is a multiplication equation.  So I substituted 600 in the for the area and 30 in for the width.  In order to solve this equation, I have to do the inverse and divide both sides by 30 which results in a length of 20.  I checked this by multiplying 20 by 30 to see if made 600.  So impressed.

Most students knew they could divide 600 by 20, but they didn't make the mathematical and strategical leap like this student did.  Using the above method is the goal I have for my students.  Seeing patterns and making generalizations uses MP 7 and MP 8 which is one of the hardest practices to implement.

A great connection
Connection to Prior Knowledge: A great connection

Finding the Area of a Rectangle

Unit 8: Geometry
Lesson 1 of 17

Big Idea: Understanding area and using formulas is a skill used in Algebra and Geometry.

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Standards:
Subject(s):
Math, volume (3-D Geom), surface area, area of rectangle
85 minutes

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