Question

A pentagonal prism is cut by a plane perpendicular to the base. What is the shape of the cross section that is formed?

Answer 1

when the plane cuts three faces of the cube, separating one corner from the others

when the plane passes through a pair of vertices that do not share a common face

when the plane is perpendicular to the base and intersects two adjacent vertical faces

when the plane makes an acute angle to the base and intersects three vertical faces

not enough information to answer the question

Answer 2

@ibrafacts @DivineSolar Help please :(

Answer 3

Okay, so first, let's think about what a perpendicular cut is - it's a cut that goes the opposite direction as the bottom of the shape, right?

Answer 4

@wach right

Answer 5

like this

Answer 6

Ok... so now what do I do?

Answer 7

Okay, so imagine the cross-section which is basically the overlapping area between the cutting plane and the prism. What shape do you think it is?

Answer 8

Pentagon?

Answer 9

or trapezoid? I am so sorry I am not very good at this @wach

Answer 10

No worries! Let's think about the shape of each side of the shape. So, we know the bottom of the prism is a flat, horizontal line, and so is the top, right? Now, what about the sides?

Answer 11

(This is if we view the plane from the side)

Answer 12

I need to go now, but: the top and bottom lines of the plane will be horizontal and the same size, because the top and bottom of the prism are the same size. The sides will be vertical and the same size for the same reason, which means the cross-section is a parallelogram, a rectangle We don't know what sizes the top/bottom and side/side are, but they will be equal to their opposite.

Answer 13

so E?