75 is 10 less than what

38 ft, 41 ft, 44 ft, 47 ft

Step-by-step explanation:

let the first piece be x, then

second piece = x + 3

third piece = x + 3 + 3 = x + 6

fourth piece = x + 6 + 3 = x + 9

sum the 4 together and equate to 170

x + x + 3 + x + 6 + x + 9 = 170, that is

4x + 18 = 170 ( subtract 18 from both sides )

4x = 152 ( divide both sides by 4 )

x = 38

Thus

first piece = x = 38 ft

second piece = x + 3 = 38 + 3 = 41 ft

third piece = x + 6 = 38 + 6 = 44 ft

fourth piece = x + 9 = 38 + 9 = 47 ft