Answer:
Your answer is True
Explanation:
A rectangle is a plane figure bounded by four sides with all angels right.
A rhombus is a plane figure bounded by four sides with all sides equal.
A square is a plane figure bounded by four sides with all angels right and all sides equal.
If a quadrilateral is both rectangle and a rhombus then the quadrilateral will have all angels right and all sides equal. which is definition of a square.
Therefore, if a quadrilateral is a rectangle and also a rhombus then it is a square.