Monday

September 1, 2014

September 1, 2014

Posted by **Xian** on Thursday, December 26, 2013 at 5:38pm.

- Math -
**Damon**, Thursday, December 26, 2013 at 5:57pm4 pi r^2 = (xyz)pi

(4/3) pi r^3 = (ijk) pi

4 r^2 = xyz

(4/3) r^3 = ijk

(4/3) r^3 is an integer less than 1000

and greater than 99

if (4/3) r^3 = 1000 r is 9.08 so try 9

if r = 9, (4/3)r^3 = 972 , the biggest we can have for r^3 criterion

now if (4/3) r^3 = 100 r is 4.21

so smallest r for this criterion is

r = 5

so far we have

5 , 6, 7, 8 , 9

BUT we need to do the area thing

4 r^2 = xyz

if xyz = 1000, r = 15.8

So

15 is the biggest for the area

if xyz = 100, r = 5 exactly

so between 5 and 15

so

5,6,7,8,9 seem to work, five of them

- Math -
**Steve**, Thursday, December 26, 2013 at 7:37pmBut 4/3 r^3 must be an integer, so r must be a multiple of 3.

I'd say only 6 and 9 are available

- Math -
**Damon**, Thursday, December 26, 2013 at 9:25pmYes, of course, sorry

**Answer this Question**

**Related Questions**

Physics - Sphere 1 has surface area A1 and volume V1, and sphere 2 has surface ...

surface area and volume - I really need some help, I don't fully understand. ...

math: advanced geometry - if the surface area of a sphere equals the surface ...

math - The earth has a radius of 6,380 km. The formula for the volume of a ...

Calculus (Parts A and B done, just help with C) - The radius, r, of a sphere is ...

Math- Radius - The volume of a sphere is V = 14,130 ft3. What is its surface ...

MAth - A sphere has a surface area of 28.26 in2. Find the diameter in inches, of...

calculus *improper integrals* - A hole of a radius of 1cm is pierced in a sphere...

calculus - A hole of a radius of 1cm is pierced in a sphere of a 4cm radius. ...

math - direct variation the surface area of a sphere varies directly as the ...