Exercise 18 Page 518

Let's begin with recalling the Properties of Squares.

1. All four sides are congruent.
2. All four angles are right angles.
3. Diagonals are both congruent and perpendicular, and they also bisect each other.

In our exercise we are given that a landscaper confirmed that each side of this quadrilateral is congruent, and its diagonals are perpendicular.

This is not enough information to be sure that the garden is a square, as we do not know anything about the angles of this figure or whether the diagonals are congruent. However, this is enough information to state that this garden is a rhombus.