Is this a trick question? Answer: All things being equal, they are all equal. ;) But seriously, if you are trying to figure the hypotenuse to check for squareness, simply measure each diagonal until they are equal and forget about Pythagoras. Then you are all square and equal, opposite and adjacent. Yehaw!
square and a rectangle
square
Diagonally opposite angles of a rectangle or square is one example.
None!!!! Every face is angles to its adjacent and opposite faces.
The adjacent sides of a square are perpendicular.
Adjacent corners of a square share one side. Opposite corners share no sides.
Each side of the square has two sides adjacent to it. Ex. if you just look at only one side, the sides next to it are the adjacent sides, not the one opposite of it.
square and a rectangle
Move two adjacent coins, leaving the other pair of adjacent coins untouched. Place them on opposite sides of the unmoved pair, so that they become diagonally opposite corners of the new square.
In a square adjacent sides are perpendicular to each other and opposite sides are parallel to each other.
Diagonally opposite angles of a rectangle or square is one example.
square
Adjacent corners of a square share one side. Opposite corners share no sides.
None!!!! Every face is angles to its adjacent and opposite faces.
The adjacent sides of a square are perpendicular.
A quadrilateral with 4 right angles and opposite sides that are parallel can be either a rectangle if the adjacent sides are of different length or a square if the adjacent sides are of the same length.
All four sides of a square are equal in length. Only the opposite sides of a rectangle are the same length. The adjacent sides are different in length.