Question

A triangular pyramid is cut by a plane. In which case is the cross section a quadrilateral?

Answer 1

@maurosalcido

Are these the options?

a) when the plane is perpendicular to the base and passes through the apex

b) when the plane is parallel to the base of the pyramid

c) when the plane intersects the base and two lateral faces of the pyramid

d) when the plane intersects the base and all three lateral faces of the pyramid