Final answer:
Without dimensions of the structure, it's impossible to determine if William's calculation of 9.75 in² of vinyl to cover the front and top is correct. To verify, one must calculate the surface area for both the front and top of the structure.
Step-by-step explanation:
Before we can determine whether William is correct, we need to calculate the surface area of the front and the top of the structure that he wants to cover with a different color vinyl. Unfortunately, the question does not provide the dimensions of the structure, so it is impossible to accurately verify his estimate without additional information. To calculate the amount of vinyl needed, you would multiply the length by the height for the front piece and the length by the width for the top piece, then sum the two areas to get the total surface area in square inches.