Final answer:
The area of the top of the triangular plate is 40 square inches.
Step-by-step explanation:
To find the area of a triangle, you can use the formula: area = 1/2 x base x height. In this case, the base of the triangular plate is 5 inches and the height is 16 inches. Plugging these values into the formula, we can calculate the area as: area = 1/2 x 5 inches x 16 inches = 40 square inches. Therefore, the area of the top of the plate is 40 square inches, option a).