This applet will help you to visualize what's going on when we build a solid from known cross sections.[br][br]The "X" slider allows you to move the single cross section along the interval [0,1][br]The "n" slider allows you to choose how many of each cross section will be displayed.[br][br]You can choose to view squares, equilateral triangles, or semi-circular cross sections perpendicular to the x-axis.  You can also click on the 3D graph and rotate and revolve the view to get a better sense of what the solid looks like.[br][br]If you enjoy this applet, check out my other Geogebra applets, and my YouTube channel, where you'll find Calculus and Geometry tutorial videos, as well as my Math Raps!  [br]https://www.youtube.com/user/MikeDobbs76