rhombus
You cannot. It is not possible to calculate the area of a quadrilateral given only its side lengths. This is because, in general, it is not a rigid shape: it can be squashed in much the same way that a square can be squashed into a rhombus which has a smaller area.
rhombus
Rhombus
A rhombus
An impossible shape
rhombus
rhombus
Rhombus?
You cannot. It is not possible to calculate the area of a quadrilateral given only its side lengths. This is because, in general, it is not a rigid shape: it can be squashed in much the same way that a square can be squashed into a rhombus which has a smaller area.
A rhombus has four equal sides but no right angles.
A rhombus
Overall
An ellipse is a shape that could be described as looking like 'a squashed circle.' With no straight edges, this shape is also called an oval.
Oval or ellispe is a shape like a slightly squashed circle.
If you squahsed a square you would first get a quadrilateral, and if you squashed it all the way, you would be left with a line segment.
The only regular geometric shape that fits your description would be an elipse. That is a circular shape so it has no straight edges, and appears to be a squashed circle.