A Square!
square
Yes
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.
Depending on your definition of "opposite", a square, rectangle, or regular parallelogram have opposite sides and opposite angles of equal measure.
Equilateral
The answer depends on what shape the question is about.
Yes, a parallelogram has four sides and four internal angles, the opposite side lengths are equal and the opposite angles are equal.
Quadrilaterals
A cuboid has 6 faces: bottom, top, front, back, left side, right side.