5
There can be a quadrangular pyramid or a quadrangular prism or other quadrangular shapes. "Quadrangular" is an adjective, not a noun. You need to be more specific.
A quadrangular is an adjective, not a noun. A quadrangular pyramid will have a different number of faces from a quadrangular prism, for example.
8
5
five
3 faces
Eight edges.
6
It has 5 sides
It has 5 sides
A quadrangular refers to something that has four sides or angles, often used to describe shapes like squares or rectangles.
An octagonal pyramid has eight sides to it