Answer:
the answer is 4
Explanation:
let x= length of the first piece.
second piece is 2x, right
third piece x+5, right
Total, in x-talk, is x + 2x + x+5 and that equals 21 feet, right.
Combine like terms: 4x + 5 = 21. Still with me?
So 4x = 16 (do you see why?)
So, what x must x be is 4