Trapezoid Calculator

This solves a trapezoid rather than only measuring it. Give all four sides, or the two parallel sides with the height, or the two parallel sides with the height and one base angle, and it returns the height, area, perimeter, median, both diagonals and all four angles, with a scale drawing of the figure. The four sides fix the shape completely, so the page works out the offset of the short side over the long one and derives everything from that. When the sides cannot close into a trapezoid it says so instead of returning a number.