7th Grade · Geometry

Composite Figure

7.G.B.6

Definition

A shape made up of two or more basic geometric shapes. Find the total area by decomposing (breaking apart) and adding the areas of the individual shapes.

Examples

  • Two rectangles, 5m×6m = 30m2 and 3m×4m = 12m2, total 42m2.
  • Subtract method: full rectangle 8 × 6 = 48, minus missing 3 × 2 = 6, gives 42m2 — same answer.

Key rule

Decompose the figure, find each area separately, then add them together.

Memory hook

Break the shape into pieces you already know how to measure.