A polygon with 4 parallel sides and an angle of 45 degrees each is called a rhombus.
A rhombus is a special type of quadrilateral where all sides have equal length, and opposite sides are parallel. The angles in a rhombus can vary, but in this case, if each angle is 45 degrees, it actually becomes a square. So technically, if we strictly adhere to the angles, we would refer to it as a square. However, if we are focusing only on the aspect of having parallel sides and equal lengths with 45-degree angles, then it’s often acknowledged as a rhombus.