(1) I assume periphery is perimeter.

(2) Area of a trapazoid with height h and bottom base length b1 and top base length b2 (bases are the parallel sides: (b1 + b2)/2 * h; it doesn't matter whether or not it is symetric: the central rectangle yeilds b2*h for the area and the remaining tail ends can be combined into a triangle with height h and base b1-b2 and the area of that is (b1 - b2) * h / 2 so total area is

h * (b2 + (b1 - b2)/2) = h * (b2 + b1/2 - b2/2) = h * (b1 + b2)/2

-bcl

(2) Area of a trapazoid with height h and bottom base length b1 and top base length b2 (bases are the parallel sides: (b1 + b2)/2 * h; it doesn't matter whether or not it is symetric: the central rectangle yeilds b2*h for the area and the remaining tail ends can be combined into a triangle with height h and base b1-b2 and the area of that is (b1 - b2) * h / 2 so total area is

h * (b2 + (b1 - b2)/2) = h * (b2 + b1/2 - b2/2) = h * (b1 + b2)/2

-bcl