10.2Area of Triangles and Quadrilaterals
Quick Answer
Triangle: A = ½bh. Rhombus and kite: A = ½d₁d₂ (product of diagonals divided by 2). These formulas follow from decomposing figures into rectangles or using the base-height relationship.
Essential Question
How can the diagonal lengths of a rhombus or kite be used to find its area without knowing the base and height?
Learning Goals
- 1Apply the triangle area formula A = ½bh.
- 2Apply the rhombus and kite area formula A = ½d₁d₂.
- 3Find the area of a quadrilateral by decomposing it into triangles.
- 4Use the coordinate plane to find areas of polygons.
Key Vocabulary
Diagonal area formula
For a rhombus or kite: A = ½d₁d₂, where d₁ and d₂ are the lengths of the diagonals.
Decomposition
Breaking a complex figure into simpler shapes whose areas can be calculated separately.
Full lesson content coming soon
Worked examples, guided practice problems, a workbook, quiz, and downloadable PDF resources will be added to this lesson in Phase 2. The learning goals and vocabulary above reflect the complete lesson scope.