5. A quadrilateral with all four sides equal is either a square or a rhombus. If the angles are not 90° it is a rhombus. There are other types of quadrilaterals as well.

Quadrilaterals
NAME SHAPE DEFINITION
square
all sides equal, all angles 90°
rectangle
opposite sides equal, all angles 90°
parallelogram
opposite sides equal, opposite sides parallel
rhombus
all sides equal, opposite sides parallel
kite
two pairs of adjacent equal sides
trapezoid
one pair of opposite parallel sides
isosceles trapezoid
one pair of opposite parallel sides, other pair equal