The cross section is a circle. The figure given below shows the intersection of a triangular prism and a plane. The cross section is a triangle. A three-dimensional figure can have several different cross sections depending on the position and the direction of the slice.
The cross section in a right rectangular prism is a polygon whose maximum number of sides equals the number of faces (surfaces) of the prism, thus it is NOT possible to have a circular cross section in a rectangular prism. Hope this helped! Good Luck!
