Final answer:
To find out how many 1 ¼' by 3' pieces can be cut from a 3'9' sheet of plywood, convert the measurements to inches and calculate the area of one piece. Then, divide the total area of the plywood sheet by the area of one piece to find the number of pieces that can be cut. The answer is 8 (D).
Step-by-step explanation:
To find out how many 1 ¼' by 3' pieces can be cut from a 3'9' sheet of plywood, we need to convert the measurements to the same units. We can start by converting the dimensions of the plywood sheet to inches. 3 feet is equal to 36 inches, and 9 inches is equal to 108 inches. Therefore, the sheet of plywood measures 36 inches by 108 inches.
Now, we can determine the number of 1 ¼' by 3' pieces that can be cut. 1 ¼' is equal to 1.25 inches, and 3' is equal to 36 inches. The area of one piece is calculated by multiplying the length and the width, so the area of one piece is 1.25 inches multiplied by 36 inches, which equals 45 square inches.
To find how many pieces can be cut from the plywood sheet, we divide the total area of the plywood sheet (36 inches by 108 inches) by the area of one piece (45 square inches). This calculation gives us a result of approximately 8 pieces. Therefore, the answer is 8 (D).