Finding the Fourth Proportional to 2,071.12, 2,858.12 and 1,139.60

Step by Step Solution

1. Step 1: Write the proportion equation
   2,071.12 : 2,858.12 = 1,139.60 : x
2. Step 2: Convert to fraction form
   2,071.12/2,858.12 = 1,139.60/x
3. Step 3: Cross multiply
   2,071.12x = 2,858.12 × 1,139.60
4. Step 4: Simplify right side
   2,071.12x = 3,257,113.55
5. Step 5: Solve for x
   x = 3,257,113.55/2,071.12
6. Step 6: Final answer
   x = 1,572.63