Jorge draws a rectangle measuring 3 ft. by 2 ft. Then, he dilates the rectangle so it is 7.5 ft. by 5 ft. If x represents the area of the original rectangle, which expression can he use to discover the area of the dilated rectangle?

A. x + (2.5)^2
B. x(2.5)
C. x(1.5)^2
D. x(2.5)^2

1 answer

To find the area of the dilated rectangle, we can first calculate the area of the original rectangle and establish a relationship with the area of the dilated rectangle.

  1. Calculate the area of the original rectangle: \[ \text{Area}_{\text{original}} = \text{length} \times \text{width} = 3 , \text{ft} \times 2 , \text{ft} = 6 , \text{ft}^2 \] So, \(x = 6 , \text{ft}^2\).

  2. Calculate the area of the dilated rectangle: \[ \text{Area}_{\text{dilated}} = \text{length} \times \text{width} = 7.5 , \text{ft} \times 5 , \text{ft} = 37.5 , \text{ft}^2 \]

  3. To find the scaling factor (dilation factor), we can divide the dimensions of the dilated rectangle by those of the original rectangle:

    • The length dilation factor is \( \frac{7.5}{3} = 2.5 \)
    • The width dilation factor is \( \frac{5}{2} = 2.5 \)

Since the rectangle is dilated uniformly, the area of the dilated rectangle is related to the area of the original rectangle by the square of the dilation factor: \[ \text{Area}{\text{dilated}} = \text{Area}{\text{original}} \times ( \text{dilation factor} )^2 \] Substituting the values: \[ \text{Area}_{\text{dilated}} = x \times (2.5)^2 \]

Thus, the correct expression Jorge can use to discover the area of the dilated rectangle is: \[ \boxed{D. , x(2.5)^2} \]