圓周問題 (附圖)

First, extend your graph to a cone, draw lines on each different heights,so you can see there are 7 triangles and they are similar trangles,therefore if you count from bottom for 100cm ,the height of triangle is 7/8 of the big one, so diameter equals to 1570.79*7/8 cm
at last repeat this calculation to find the diameters.

你個問題都唔清楚, 你o既700cm係底數上去定上數落去?? 你講o既圓係問緊上底定下底?