How to change posterpage setup to 48" in height and 96"in length

[pptuser]

I need to make a poster of 96" in length and 48" in height but I am unable to
do so in the page setup of power point.

 

[Echo S]

I need to make a poster of 96" in length and 48" in height but I am unable to
do so in the page setup of power point.

You'll have to specify a page size half the size you want and print at 200%.
So, for 96 x 48, set it to 48 x 24 in File/Page Setup.

Print posters or other large format output
http://www.rdpslides.com/pptfaq/FAQ00537.htm has more info.