Answer: RHOMBUS
Step-by-step explanation:
The name of a polygon that has four congruent sides with the angles measuring 60°, 120°, 60° and 120° is rhombus.
According to the properties of a rhombus, the opposite angles are equal and opposite sides are parallel.
However, the adjacent angles of rhombus are supplementary which means that they add up to 180°.
For example:
60° + 120° = 180°
