Final answer:
To cut 1 ¼' by 3' pieces from a 3' × 9' sheet of plywood, divide the area of the sheet by the area of one piece and take the whole number less than or equal to the quotient.
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 calculate the area of one piece and the area of the sheet.
The area of one 1 ¼' by 3' piece is (1.25 * 3) = 3.75 square feet.
The area of the 3' × 9' sheet is (3 * 9) = 27 square feet.
To determine the number of pieces that can be cut, divide the area of the sheet by the area of one piece: 27 / 3.75 = 7.2.
Since we can't have a fraction of a piece, the closest whole number less than or equal to 7.2 is 7. Therefore, you can cut 7 1 ¼' by 3' pieces from a 3' × 9' sheet of plywood.