The radius of the pizza is 6 inches, so each slice is 6 inches long.
there are 8 pieces, so the outside radius of each slice would be the circumference divided by the number of pieces:
37.68 / 8 = 4.71 inches.
You can estimate the height of the parallelogram as the length of a slice = 6 inches and the width of it as 8 x 4.71 = 37.68 inches.
The approximate area would be length x width = 37.68 x 6 = 226.08 square inches.