Answer
Find out the what is the constant proportionality .
To prove
Formula
Area of rectangle = Length × Breadth
As given
Marielle’s painting has the dimensions shown (Painting Width = 18 inches, Painting Length = 24 inches).
Area of the original painting = 18 × 24
= 432 inches²
As given
The school asks her to paint a larger version that will hang in the cafeteria.
The larger version will be twice the width and twice the height.
Length of the larger version painting = 2 × 18
= 36 inches
Breadth of the larger version painting = 2 × 24
= 48 inches
Now area of the larger version painting = 36 × 48
= 1728 inches²
As given
The area of the original painting proportional to the area of the larger
painting .
Thus
Where k is the constant of proportionality
Putting the value
432 = k × 1728
k = 4
The constant proportionality is 4 .
Hence proved