Finding the Fourth Proportional to 1,978.94, 2,730.85 and 1,139.67

Step by Step Solution

1. Step 1: Write the proportion equation
   1,978.94 : 2,730.85 = 1,139.67 : x
2. Step 2: Convert to fraction form
   1,978.94/2,730.85 = 1,139.67/x
3. Step 3: Cross multiply
   1,978.94x = 2,730.85 × 1,139.67
4. Step 4: Simplify right side
   1,978.94x = 3,112,264.97
5. Step 5: Solve for x
   x = 3,112,264.97/1,978.94
6. Step 6: Final answer
   x = 1,572.69