Here's the question you clicked on:
Denebel
A solid has a circular base of radius 3. If every plane cross section perpendicular to the x- axis is an equilateral triangle, the. It's volume is..
??? couldn't picture at all
*then, it's volume is ...
|dw:1334049066451:dw|imagine a bunch of triangles popping out in the z-direction
circle: x^2 + y^2 = 9 --> y = sqrt(9-x^2) |dw:1334048930933:dw| volume is sum of all the areas of the triangles area = sqrt3/4 *(2y)^2 = sqrt3 y^2 = sqrt3(9-x^2) \[V = \sqrt{3}\int\limits_{-3}^{3}(9-x^{2}) dx\]
^what dumbcow said|dw:1334049136750:dw|