g.p

let S1,S2.... be squares such that for each n>or=1, the length of a side of Sn equals the length of a diagonal of Sn+1 . If the length of a side of S1 is 10cm , then for which of the following values of n is the area of sn less than 1 sq.cm
a)7 b)8 c)9 d)10

4 Answers

11
Anirudh Narayanan ·

If side of S1 is a, then side of S2 is a/√2, side of S3 is a/2 and so on...
Hence if area of S1 is A, then area of S2 is A/2 and so on.......
Area of Sn=A/(2)n-1

Can you carry on from here?

11
Anirudh Narayanan ·

If what i've given above is correct, then answer should turn out to be 8.
If my above method is wrong then I'm extremely sorry for wasting your time

1
skygirl ·

it will not only be 8..

inequality is given...

u r absolutely correct..

Sn < 1

=> 100 < 2n-1 => 26 < 2n-1 (coz 27>100)

=> 6< n-1 => n>7

so ans is... b,c,d ........ i mean 8,9,10.

11
Anirudh Narayanan ·

yup got it [4]

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