Final answer:
The total area of the 7 magazine pages Ms. King used on the bulletin board is 24,570 square feet, calculated by multiplying the area of a single page (3510 square feet) by the number of pages (7).
Step-by-step explanation:
To calculate the total area of all the magazine pages Ms. King used on the bulletin board, we first find the area of a single magazine page and then multiply it by the number of pages she used. The area of one magazine page can be found using the formula for the area of a rectangle, which is length × width.
The area of one magazine page is 78 feet × 45 feet, which equals 3510 square feet. Since Ms. King used 7 magazine pages, the total area covered is 7 × 3510 square feet, which equals 24,570 square feet. Therefore, the magazine pages cover a total area of 24,570 square feet on the bulletin board.