To find the length of the rectangle in Spencer's new scale drawing, we need to first determine the scale factor based on the original dimensions of the rectangle.
-
Convert the original dimensions to inches:
- The original width is 12 ft, which is equivalent to \( 12 \times 12 = 144 \) inches.
- The original length is 20 ft, which is equivalent to \( 20 \times 12 = 240 \) inches.
-
Determine the scale factor: The original width of the rectangle is 144 inches, and the new width needs to be 1.5 inches. Therefore, the scale factor can be calculated as follows:
\[ \text{Scale factor} = \frac{\text{new width}}{\text{original width}} = \frac{1.5 \text{ in}}{144 \text{ in}} = \frac{1.5}{144} = \frac{1}{96} \]
-
Apply the scale factor to the original length: The original length is 240 inches. To find the new length in the scaled drawing:
\[ \text{New length} = \text{original length} \times \text{scale factor} = 240 \text{ in} \times \frac{1}{96} \]
Now calculate \( 240 \div 96 \):
\[ 240 \div 96 = 2.5 \]
Thus, the length of the rectangle in Spencer's new scale drawing is:
\[ \boxed{2.5} \text{ inches} \]