Finding the Fourth Proportional to 1,978.37, 2,730.60 and 1,139.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,978.37 : 2,730.60 = 1,139.55 : x
2. Step 2: Convert to fraction form
   1,978.37/2,730.60 = 1,139.55/x
3. Step 3: Cross multiply
   1,978.37x = 2,730.60 × 1,139.55
4. Step 4: Simplify right side
   1,978.37x = 3,111,650.96
5. Step 5: Solve for x
   x = 3,111,650.96/1,978.37
6. Step 6: Final answer
   x = 1,572.84