Yes.
A Square!
Yes, all cubes are cuboids because a cuboid is defined as a three-dimensional shape with six rectangular faces, and a cube meets this criterion with all its faces being equal squares. Therefore, while all cubes are cuboids, not all cuboids are cubes, as cuboids can have faces of different dimensions.
square
Yes
Examples of cuboids include everyday objects such as a brick, a shoebox, and a standard cereal box. Each of these items has six rectangular faces, with opposite faces being equal in size. Additionally, furniture like a rectangular table or a bookshelf can also be considered cuboids due to their similar geometric shape.
270
No, a rectangle has opposite side which are equal in length.
All quadrilaterals have two [pairs] of opposite sides and in most cases they are not equal.
Equilateral
The answer depends on what shape the question is about.
Quadrilaterals
Yes, a parallelogram has four sides and four internal angles, the opposite side lengths are equal and the opposite angles are equal.