Final answer:
The dimensions of Ginny's garden are 72 ft by 8 ft.
Step-by-step explanation:
The dimensions of Ginny's garden can be found by using the formula for the perimeter of a rectangle, which is P = 2L + 2W, where P is the perimeter, L is the length, and W is the width.
Given that the length is 9 times as long as the width, we can write L = 9W. Plugging this into the perimeter formula, we get 160 = 2(9W) + 2W, which simplifies to 160 = 20W.
Dividing both sides by 20, we find that W = 8.
Substituting this value back into the equation L = 9W, we get L = 9(8) = 72.
Therefore, the dimensions of the garden are 72 ft by 8 ft.