An equalateral triangle
triangle
a rhombus
A rhombus.
56678 Shape is called a rhombus
I only know it's not a polygon
A rhombus
The shape you are describing is a rhombus. A rhombus has all sides of equal length, and it can have two obtuse angles and two acute angles, making it a type of quadrilateral. The specific angles depend on the rhombus's proportions, but it meets the criteria you've outlined.
An isosceles triangle fits the description given or an equilateral triangle which has 3 equal sides and 3 equal acute angles.
Any shape with 4 acute angles must have more than 4 sides. Any shape with more than 4 sides can have 4 acute angles (but doesn't have to).
With no acute or obtuse angles, the shape must only have right angles. For a quadrilateral, that limits it to a square or rectangle. Because each side has a different length than the one next to it, it has to be a rectangle.(Or, it could be a shape with any amount of sides above 4, as long as the angles are all right angles)
A rhombus is a shape having two acute angles and four equal sides.
Impossible.