Home plate in the game of baseball is an irregular pentagon with two parallel sides, each perpendicular to a base. It seems reasonable to dub such a figure (i.e., a rectangle with a coincident isosceles triangle placed on one side) a "isosceles right pentagon."
Unlike the other bases, home plate is a five-sided slab of whitened rubber that is set at ground level. The dimensions of home plate are 17 inches (43 cm) across the front, 8.5 inches (22 cm) down each side, with a triangular rear of two sides of 12 inches (30 cm).
I apologize if this answer is unhelpful.
