True or false all squares have four congruent sides .since rectangles are squares all rectangles have four congruent sides

That is false. A rectangle has two sides that are congruent with each other and another two that are congruent with each other

True: All squares have four congruent sides.

Rectangles are NOT squares.

All squares are rectangles, but not all rectangles are squares.
This is because squares are a certain type of rectangle.
Rectangles are not a certain type of square.