What is parallelogram and what formula find it?
A parallelogram is a geometric shape. Opposite sides are of the same length and are parallel (Ex. a = c, b = d). Also the angles that are opposite to each other are of the same size (alpha = gamma; beta = delta). I hope this helps. Otherwise just google the shape. Your question about "how to find it" is too unprecise. What are you trying to do with the parallelogram?