Finding the Fourth Proportional to 1,978.68, 2,730.96 and 1,139.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,978.68 : 2,730.96 = 1,139.88 : x
2. Step 2: Convert to fraction form
   1,978.68/2,730.96 = 1,139.88/x
3. Step 3: Cross multiply
   1,978.68x = 2,730.96 × 1,139.88
4. Step 4: Simplify right side
   1,978.68x = 3,112,966.68
5. Step 5: Solve for x
   x = 3,112,966.68/1,978.68
6. Step 6: Final answer
   x = 1,573.25