Finding the Fourth Proportional to 1,978.22, 2,729.90 and 1,139.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,978.22 : 2,729.90 = 1,139.20 : x
2. Step 2: Convert to fraction form
   1,978.22/2,729.90 = 1,139.20/x
3. Step 3: Cross multiply
   1,978.22x = 2,729.90 × 1,139.20
4. Step 4: Simplify right side
   1,978.22x = 3,109,898.10
5. Step 5: Solve for x
   x = 3,109,898.10/1,978.22
6. Step 6: Final answer
   x = 1,572.07