Shae is covering 3 walls in her bedroom with wallpaper. The measurement of each wall is 12 ft x 14 ft. A roll of wallpaper covers 42 square feet. How many rolls should Shae purchase?

Each wall measures 12 ft * 14 ft.

Area of one wall = LW = 12 ft * 14 ft = 168 ft^2

Area of 3 walls = 3 * area of 1 wall = 3 * 168 ft^2 = 504 ft^2

One roll of wall paper covers 42 ft^2.

To find out how many rolls are needed,

divide the total area by the area of one roll.

(504 ft^2) / (42 ft^2) = 12

Answer: Shae should purchase 12 rolls.

12 x 14 = 168. 168/42 = 4