Answer:
Width: 9 inches
Explanation:
1. We can see that the height increased by 6 inches, provided a difference of 15 and 9. If the question states that the frame's dimensions were proportionately enlarged, perhaps the height's enlargment could be benificial
2. If we were to take a ratio where the increased height is over the previous height (height enlargment/prior height) that would be 6/9, or in other words, can be simplified to be 2/3
3. We can see that if the width were to be enlarged, we might be able to determine how much it should be enlarged through a proportionality, provided the frame's dimensions are proportionately enlarged. Now if x ⇒ the width enlargment: 2 / 3 = x / 5.4
4. Through cross multiplication, let us solve for x:
2 * 5.4 = 3 * x,
10.8 = 3 * x,
x = 3.6 inches by which the width should be enlarged
5. If we are to determine the new width of the frame after enlargment, add 5.4 to 3.6 ⇒ the width of the frame ⇒ 9 inches