Express an Area as an Expression by Decomposing Area (Example)

Cut the area into two. Pupils see how to use algebraic expressions to find the area of a composite figure. The video breaks the figure into two rectangles and finds the missing lengths to find the area. After multiplying the dimensions, the presenter creates a simplified expression representing the area of the entire figure.

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CCSS: Adaptable
Additional Tags
Instructional Ideas
  • Provide the class with several practice problems and have them discuss how they would decompose the figure
Classroom Considerations
  • Learners should be comfortable performing operations with algebraic expressions
  • Assumes the class knows how to find the area of non-common figures
Pros
  • Shows the way the decomposition does not affect the answer
  • Highlights key calculations with colors
Cons
  • None
Common Core