Lessons 7–11. Find the area of a polygon by decomposing it into parallelograms and triangles. Understand bases and heights in a triangle and recognize base-height pairs to use to find the area of a triangle. Understand why the process of finding the area of a triangle can be abstracted as 1/2 ∙ b ∙ h (or equivalent) and apply the formula to find the area of a triangle.