Perimeter and area of the Koch snowflake in the limit
Question
Start with an equilateral triangle of side . At each step, on the middle third of every edge erect an outward equilateral triangle whose side is one-third of that edge, and remove the middle third. Repeating forever produces the Koch snowflake. What happens to the perimeter, and what is the limiting enclosed area?
Short answer
The perimeter is infinite; the area tends to of the original triangle, i.e. . Each step multiplies the perimeter by , so it diverges. Step adds triangles each with area of the original , so the total added is .
Adapted from Wilmott, Frequently Asked Questions in Quantitative Finance, ch. 10 brainteaser 'Snowflake', p.354; question and answer rewritten by SelfMadeQuant.com.
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