18.6.4 Sector Area
Core ideaA sector is like a slice cut from a pizza, and whatever fraction of the whole circle it takes up, its area is that same fraction of pi r squared.
Module goal. Move from the circumference being pi times the diameter to arc length, sector area, and regular polygons, gathering geometry into quantities you can compute, and paving the way for the next stage's use of numbers and intervals to describe shapes.