<p>Can someone give me a brief overview of how to find the volume using cross sectional area? I’ve run into a few problems where it gives you cross sections as circles or triangles. Whats the easiest way to go about solving these?</p>
<p>V=pi*S f(g(x))dx
f(x) = the geometric figure
g(x) = the equation</p>
<p>eg…if you are given the equation y=x+3 for 0<=x<=4…and you are rotating it about the x-axis using semi circles…you would get this…</p>
<p>f(x) = .5<em>pi</em>r^2
g(x) = x+3</p>
<p>so V = pi * S .5<em>pi</em>(x+3)^2</p>