Quantcast Geometry Help? - XP Math - Forums
XP Math Home Sign Up FREE! | Sign In | Classroom Setup | Common Core Alignment PDF Version

Go Back   XP Math - Forums > Welcome > Off-Topic Discussion

Reply
 
Thread Tools Display Modes
Old 07-18-2007   #1
tochau
Guest
 
Posts: n/a
Default Geometry Help?

Two pyramids are similar with a ratio of surface areas of 25:64, Find the volume of the second pyramid given the first has a volume of 250m^3.thanks in advance.ania: when I did it your way i got 16....and i dont think that's it.doctor Q: i've never done it your way before
  Reply With Quote
Old 07-18-2007   #2
Doctor Q
Guest
 
Posts: n/a
Default

First we take the ratio-: 25:6464 / 25 = 2.56Now we cube this amount to allow for the change in area in the three axis (x,y,z)2.56^3 = 16.777216Now we multiply the 1st surface area by this....250 x 16.777216 = 4194.304 m^3NOTE!!! Now I've seen Mathmatica's way, I think he's got it correct.
  Reply With Quote
Old 07-18-2007   #3
ania
Guest
 
Posts: n/a
Default

To do this you need to find the scale factor, a:b, by square rooting the surface areas. It is 5:8.Then you set up a proportion a^3:b^3=Volume1/Volume 2Cross multiply and solve.
  Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 03:24 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
XP Math