Question

A right cylinder is sliced revealing a two-dimensional cross-section.

Which is not a possible cross-section?
circle
square
rectangle
triangle

Answer 1

easy peasy

Explanation:

imagine slicing the cylinder in your head,

there can be two possibilities,

1. slice it through length-wise (by the cylinder's length),

2. or slice it breadth-wise (by the cylinder's radius),

in the first case,

the result can be obtained in two ways,

that is if the radius of the cylinder is equal to its length, then you will obtain a square cross-section

and/or if the radius and the height are unequal, that will result in a rectangular cross-section,

hence we have two possibilities strike out, it can be in a square or rectangle cross-section

now in the second case,

we get only one possibility, that is the cross-section would be circular,

leaving us with only one option left, that would be the triangular cross-section, which we would never find if you slice the cylinder in any possible way :)