AC9M7M01 Year 7 Mathematics

Content descriptor solve problems involving the area of triangles and parallelograms using established formulas and appropriate units

Elaborations

• • Elaboration using the formula for the area of a rectangle and the array structure to derive the formula for the area of a triangle and the area of a parallelogram , given their perpendicular heights; for example, establish that the area of a triangle is half the area of an appropriate rectangle by using the spatial relationship between rectangles and different types of triangles
• • Elaboration using dynamic geometry software to demonstrate how the sliding of the vertex of a triangle at a fixed altitude opposite a side leaves the area of the triangle unchanged
• • Elaboration using established formulas to solve practical problems involving the area of triangles, parallelograms and rectangles; for example, estimating the cost of materials needed to make shade sails based on a price per metre or determining different combinations of dimensions that lead to a given area