选择题
2009 AMC 8 Problem 9: Regular Polygons Chain
Construct a square on one side of an equilateral triangle. On one non-adjacent side of the square, construct a regular pentagon, as shown. On a non-adjacent side of the pentagon, construct a hexagon. Continue to construct regular polygons in the same way, until you construct an octagon. How many sides does the resulting polygon have?
A.
21
B.
23
C.
25
D.
27
E.
29