Area of Composite Shapes (Grade 6)
A composite shape is made of simpler shapes joined together (like an L-shape = two rectangles).
Understanding area of composite shapes
Find its area by splitting it into rectangles (and triangles), finding each piece's area, and adding them up. Sometimes it's easier to find a big rectangle and subtract a missing corner.
Seeing it in action
Worked example
An L-shape splits into a 4×2 rectangle and a 2×3 rectangle. Total area?
4×2 = 8 and 2×3 = 6. Add: 8 + 6 = 14 square units.
Split the L into two rectangles, find each area, then add: 8 + 6 = 14 square units.
A common mistake, and the fix
Multiplying the outside measurements of the whole shape, or counting a piece twice.
Each piece uses its own sides: in the example the pieces are 4 × 2 and 2 × 3, so the area is 8 + 6 = 14 square units. When you can, check with the other method: the surrounding rectangle minus the missing corner should give the same area.
Try a few
Two rectangles, 3×3 and 3×2 — total area?
9 + 6.
A 5×5 square with a 2×2 corner removed — area?
25 − 4.
A 6×2 and a 2×2 joined — area?
12 + 4.
Perimeter Patrol
A calm tile-grid game for building and reading area and perimeter.
Try it in Numeris.
A short lesson, then practice with feedback on every answer.
Put the reasoning on paper.
Try six fraction, angle, perimeter and area questions with explained answers, for grades 4–6.
Free printable · 3 pagesText version (screen-reader friendly): Draw it. Explain it. Math sample
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