Finding the Fourth Proportional to 2,071.29, 2,858.38 and 1,139.79

Step by Step Solution

1. Step 1: Write the proportion equation
   2,071.29 : 2,858.38 = 1,139.79 : x
2. Step 2: Convert to fraction form
   2,071.29/2,858.38 = 1,139.79/x
3. Step 3: Cross multiply
   2,071.29x = 2,858.38 × 1,139.79
4. Step 4: Simplify right side
   2,071.29x = 3,257,952.94
5. Step 5: Solve for x
   x = 3,257,952.94/2,071.29
6. Step 6: Final answer
   x = 1,572.91