Finding the Fourth Proportional to 1,978.80, 2,730.54 and 1,139.34

Step by Step Solution

1. Step 1: Write the proportion equation
   1,978.80 : 2,730.54 = 1,139.34 : x
2. Step 2: Convert to fraction form
   1,978.80/2,730.54 = 1,139.34/x
3. Step 3: Cross multiply
   1,978.80x = 2,730.54 × 1,139.34
4. Step 4: Simplify right side
   1,978.80x = 3,111,013.44
5. Step 5: Solve for x
   x = 3,111,013.44/1,978.80
6. Step 6: Final answer
   x = 1,572.17