Which option is NOT a valid method for finding the area of a composite shape?

• A. Subdivide into triangles and rectangles and sum areas.
• B. Use the height times base for every shape as the area.
• C. Add the areas of all the tiling parts.
• D. Subtract the area of any holes from the total.

Answer: (B)

When finding the area of a composite shape, you work with pieces whose areas you know. You can cut the shape into triangles and rectangles and add those areas, or tile it with smaller shapes and sum their areas, and if there are holes, you subtract the area of those holes. The height times base rule is only reliable for simple shapes like rectangles and parallelograms that have a single base and a constant height. For more complex figures, the height would vary across the shape, so multiplying one base by a single height doesn’t give the true area. For example, an L-shaped figure can’t be measured with one base and one height without splitting it into two easier pieces. So that method isn’t universal, while subdividing, tiling, or subtracting holes are valid ways to find the area of composite shapes.