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 grappler June 11th, 2009 06:44 AM

Help with this Geometrical Problem

A pyramid has a square base. It is built out of 1m long square stone blocks. The base length is 230m. How many blocks have been used to build it?

I was able calculate that:
* Base area = 230 sq = 52900 m sq
* Height = 230/2 = 115 m
* Top area = 2 sq = 4

A blocks are taken away from each side so on the second level it has 228 blocks. a big step pyramid.

I know that I can add the square of all of the levels together and get the answer but it take a lot of time. is there an another way to calculate the amount of blocks used to build the pyramid?

 skipjack June 11th, 2009 08:22 AM

You need 2² + 4² + . . . + 228² + 230² = 4(1² + 2² + . . . + 114² + 115²). Use the second formula given here.

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