geometry
posted by Mark .
Assume there are 2 similar polygons, whose scale factor is 4:5. If the larger polygon has an area of 30 units squared, what is the area o the smaller polygon?

Areas of similar triangles are proportional to the square of their corresponding sides.
area of smaller/area of larger = 4^2/5^2
area of smaller /30 = 16/25
area of smaller = 30(16/25) = 96/5 or 19.2