Finding the Fourth Proportional to 1,978.29, 2,730.31 and 1,139.13

Step by Step Solution

1. Step 1: Write the proportion equation
   1,978.29 : 2,730.31 = 1,139.13 : x
2. Step 2: Convert to fraction form
   1,978.29/2,730.31 = 1,139.13/x
3. Step 3: Cross multiply
   1,978.29x = 2,730.31 × 1,139.13
4. Step 4: Simplify right side
   1,978.29x = 3,110,175.18
5. Step 5: Solve for x
   x = 3,110,175.18/1,978.29
6. Step 6: Final answer
   x = 1,572.15