Final answer:
To find the area of a right triangle, you need the base and height. Without those measurements, we cannot calculate the area.
Step-by-step explanation:
To find the area of a right triangle, you can use the formula: Area = 1/2 × base × height. In this case, the base and height of the triangle are not given, so we cannot directly calculate the area. Therefore, none of the options provided (a) 8.5 in., (b) 6 in., (c) 18 square inches, or (d) 20.5 square inches can be considered as the correct answer. Additional information is needed to find the area of the cloth.