Finding the Fourth Proportional to 1,978.94, 2,731.27 and 1,139.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,978.94 : 2,731.27 = 1,139.50 : x
2. Step 2: Convert to fraction form
   1,978.94/2,731.27 = 1,139.50/x
3. Step 3: Cross multiply
   1,978.94x = 2,731.27 × 1,139.50
4. Step 4: Simplify right side
   1,978.94x = 3,112,287.56
5. Step 5: Solve for x
   x = 3,112,287.56/1,978.94
6. Step 6: Final answer
   x = 1,572.70