pentagonal prism
Yes, that's what makes them congruent!
Two geometric shapes are similar if they have same size,shape, side lengths,and angles.
Thinking about the two dimensional equivalent, sharp corners basically waste perimeter while encompassing little additional area. As you increase the number of corners in a shape, you end up carving out more area for the same input of perimeter. As a shape's number of sides approaches larger and larger numbers, it rounds out to the point where you can think of a circle as a shape with infinite number of sides and corners. The same goes for three dimensional figures, substituting volume for area. Essentially, sharp corners are wasteful, the more corners you have the less wasteful they are, so if you have an infinite number of corners, you'll be enclosing the most volume/area with minimum surface area/perimeter.
Because a prism is always made of two identical 2-d shapes connected to each other. Any number*2 is even. So, any number of corners on a given 2-d shape will become twice that, and thus even, when made into a prism.
A square and rectangle are two of them out of many many more
There are an infinite number of shapes in this world. It would help both of us if you could be more specific. Regular or irregular, two-dimensional or three-dimensional, corners or vertices, etc.
pentagonal prism
Only if they have the same number of sides.
cube and cuboid
Triangle
1 is the triangle
Yes, that's what makes them congruent!
Rectangular prism Cube
If there are two 90 degree angles on the shape (example: squares or rectangles' corners)
A cube and a rectangular prism.
the same number of sides and internal angles but not the length of the sides.