Since we don't know the original length, we will call it x. The new garden will have a length 3 meters longer than the original so the new length will be x+3 meters. The area of a rectangle is found with the formula
a = length × width
To find the area of the new garden we will use the new measurements
x+3 × 5 = 90
x + 3 = 90/5
x + 3 = 18
x = 15
Since we know the length of the original garden was 3 meters less than the new one, then
15 - 3 =
12 meters was the original length.
