Atriangular pyramid is cut by a plane. in which case is the cross section a quadrilateral?
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

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

Step-by-step explanation:

We know that a triangular pyramid has four faces. Thus to create a quadrilateral, the intersecting plane must intersect all four faces.

From all the given options only in option D the plane will intersects all the four faces producing a closed polygon of four lines such that the cross section will be a quadrilateral.

hence, the right answer is " When the plane intersects the base and all three lateral faces of the pyramid, the cross section of the triangular pyramid will be a quadrilateral."

what's the question?

step-by-step explanation:

there is no question.

94

step-by-step explanation:

average the numbers and use a variable to figure out the minimum to get a 90.

(79+94+91+92+x)/5=90

x = 94