Answer:
20ft
Step-by-step explanation:
Quick reasoning: pick the ratio and start adding both values as many times as you reach the value you need: You start with 11:5, add once, you get 22:10; add again, you get 33:15. Add one final time, you get 44:20.
More rigorous: You want to see how many times the length fit in the ratio: that means dividing the length by the first term of the ratio, or 44/11 = 4. At this point you multiply the second term by the number you just found, ie 5x4= 20.
