Finding the Fourth Proportional to 1,978.62, 2,730.59 and 1,139.45

Step by Step Solution

1. Step 1: Write the proportion equation
   1,978.62 : 2,730.59 = 1,139.45 : x
2. Step 2: Convert to fraction form
   1,978.62/2,730.59 = 1,139.45/x
3. Step 3: Cross multiply
   1,978.62x = 2,730.59 × 1,139.45
4. Step 4: Simplify right side
   1,978.62x = 3,111,381.94
5. Step 5: Solve for x
   x = 3,111,381.94/1,978.62
6. Step 6: Final answer
   x = 1,572.50