Area Decomposition Posters
Area Detective Grade 6 SPED Tool
PARALLELOGRAM TO RECTANGLE
We can SLICE a shape and SLIDE the piece to make a simple rectangle. The total area does not change!
1. Parallelogram Each grid square = 1 unit × 1 unit 2. New Rectangle
✂️ CUT HERE Height = 3 Base = 4 SLIDE Height = 3 Base = 4
3 EASY STEPS TO SOLVE:
1
SLICE IT!
Find the straight height line. Cut the Red Triangle off the left side of your parallelogram.
2
SLIDE IT!
Slide the Red Triangle to the right side to fill the gap. It is now a perfect Rectangle!
3
SOLVE IT!
Count the grid squares inside the shape OR multiply: Base × Height.
Total Area
4 × 3 = 12
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Remember: Decomposing means cutting a shape into parts. Rearranging means moving those parts. The space inside (Area) stays exactly the same!
Area Detective Decomposition Method
MIXED IRREGULAR POLYGONS
Split complex shapes into simple shapes you already know. Solve for each part, then add them up!
Example: Space Rocket Each grid square = 1 unit × 1 unit
B A C Base = 4 Ht = 2 Height = 3 Bottom Base = 6 units Height = 2
THE 3-STEP BREAKDOWN:
1
DECOMPOSE (SPLIT IT UP)
Split the complex rocket into 3 simple parts: B: Triangle Nose, A: Rectangle Body, and C: Trapezoid Booster.
2
Solve Parts
CALCULATE EACH AREA
Shape B (Nose) (4 × 2) ÷ 2 Area = 4
Shape A (Body) 4 × 3 Area = 12
Shape C (Booster) ((4+6)÷2)×2 Area = 10
3
SUM THEM UP!
Add all three parts together to get the total area.
Total Area 4 + 12 + 10 = 26
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SPED Strategy TIP: When kids struggle with formulas, they can always **count the individual squares** on the grid background to verify their math answers!
