Question

Someone please help this is my last question.

Answer 1

okay so the first square is 15, next would be 13.5, then 12.15? then what do I do?

Answer 2

use the formula :
S = a1/(1-r)

here known a1 = 15 and r = 90/100 = 9/10

Answer 3

when am I supposed to stop calculating?

Answer 4

this is an infinitely geometric progression, so the calculation would be take by limit nearest. use the formula above :)

Answer 5

I do s=15/(1-9/10) and get 150

Answer 6

that's right !

Answer 7

how is that right, the perimeter is supposed to get smaller not bigger though

Answer 8

Or am I supposed to be finding the perimeter of all the squares together and not single ones.

Answer 9

have you learned about infinite geometric series before ?

Answer 10

We just started in school today learning about it, geometric and arithmetic.

Answer 11

this site might useful to understanding about "infinite geo series"
http://en.wikipedia.org/wiki/Geometric_series

Answer 12

btw, your series is
15 + 13.5 + 12.15 + ....

Answer 13

That is so confusing so should I just tell my teacher I need more help and can't do this question.

Answer 14

I mean the link is confusing.

Answer 15

okay, u found this series becomes 15 + 13.5 + 12.15 + ....
we knowed that it is an infinite geo series with the frist term (a1) = 15 and the ration (r) = 90/100=9/10. now we can use the formula above to get the ending of calculation of that series :

S = a1/(1-r)

Answer 16

okay so I was correct about the 15+13.5+12.15..... then the last perimeter would be 150, but how would that be the last perimeter when they are supposed to keep getting smaller or does the 150 mean that my series would have 150 numbers.

Answer 17

150 is the total of all the perimeters, we cant know what's the last perimeter of this series , because this is an "infinity series" :)

Answer 18

okay so I was looking for the total of all of the perimeters. the question was really confusing to me. So it was wanting me to find the series and the sum of all of the numbers in the series. My series would be 15+13.5+12.15..... and the total of all the numbers would be 150. Thank you so much for helping me.

Answer 19

you're welcome
sorry if my explanation not make more sense :)