Area of an irregular polygon
An irregular polygon is drawn on a numbered grid where each block is 1 cm². The student finds its area.
The corners sit on grid points, so the shape can be split into rectangles and right triangles, or drawn inside a rectangle with the corner triangles taken away.
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What changes each time
- Polygons with four or more corners
- Corners anywhere on a 15 × 15 grid
- A new shape every time
More area, perimeter and volume practice
- Area by counting squares (Grade 2)
- Area and perimeter of a square (Grade 3)
- Area and perimeter of a rectangle (Grade 3)
- Area with half squares (Grade 3)
- Area of an L-shape (Grade 3)
- Perimeter of an L-shape (Grade 3)
- Draw a rectangle with a given area and perimeter (Grade 3)
- Missing side of a rectangle (Grade 4)
- Rectangle sides from a ratio (Grade 4)
- Area of a right triangle (Grade 4)
- Area of an isosceles triangle (Grade 4)
- Area of a scalene triangle (Grade 4)
- Missing triangle in a square (Grade 5)
- Volume by counting cubes (Grade 5)