I think that the D. CONE is the three-dimensional figure that will be formed when an equilateral triangle is rotated around the x-axis of the coordinate plane.
<span>A sphere is defined as the set of all points in space that are a fixed distance from a common point, the center. </span> <span>A cylinder is with two parallel congruent circular faces whose cross sections (taken parallel to these circular faces) are circular. </span> <span>A cube is a rectangular prism whose faces are squares.</span>
