A cube of edge 2cm is inscribed in a cylinder with an altitude of 4 cm. Find the volume of the cylinder?

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- Mar 22nd 2010, 08:51 PMreiwardCube
A cube of edge 2cm is inscribed in a cylinder with an altitude of 4 cm. Find the volume of the cylinder?

- Mar 23rd 2010, 02:42 AMGrandad
Hello reiwardDraw a

*plan*view of the cube inscribed in the cylinder, and you'll get a square of side $\displaystyle 2$ cm inscribed in a circle. If the radius of the circle (and therefore also the cylinder) is $\displaystyle r$, then:

$\displaystyle r^2 = 1^2 + 1^2$Now use the formula $\displaystyle V = \pi r^2 h$ to find the volume of the cylinder.

Grandad - Mar 23rd 2010, 07:59 AMreiward
Can i use the formula

R = e / ( 2 sin theta/2 )

R = 2 / 2 sin 45

R = square rt of 2? - Mar 23rd 2010, 08:25 AMGrandad