True
If you are talking about the diagonals of a quadrilateral, the only quadrilateral that have diagonals that are perpendicular and bisect each other is a square, because a rectangle has bisecting diagonals, while a rhombus has perpendicular diagonals. And a square fits in both of these categories.
A rectangle is an example of a quadrilateral where the diagonals are congruent and bisect each other. However, a kite is a quadrilateral that can also have congruent diagonals, but they do not bisect each other. In a kite, one diagonal bisects the other at a right angle, while the other diagonal remains unequal in length. Therefore, while both shapes can have congruent diagonals, only the rectangle has diagonals that bisect each other.
diagonals.
may or may not be
always
Square
True
True
If you are talking about the diagonals of a quadrilateral, the only quadrilateral that have diagonals that are perpendicular and bisect each other is a square, because a rectangle has bisecting diagonals, while a rhombus has perpendicular diagonals. And a square fits in both of these categories.
true
The missing word is "bisect".
diagonals.
Square, Rhombus
True
may or may not be
A quadrilateral is a parallelogram if and only if its diagonals bisect each other (this should be in any geometry book)