Learning goals: Teacher Facing Estimate the area of a complex, real-world region, e.g., a state or province, by approximating it with an irregular polygon, and indicate that it is an approximation when expressing the answer (orally and in writing). Explain (orally and in writing) how to calculate the area of an irregular polygon by decomposing it. Interpret floor plans and maps in order to identify the information needed to calculate area. Full lesson plan (warm-up, activities, synthesis, cool-down prompt) from 7.3 Measuring Circles, Grade 7.