Finding the Fourth Proportional to 6,139.98, 9,210.81 and 1,978.60

Step by Step Solution

1. Step 1: Write the proportion equation
   6,139.98 : 9,210.81 = 1,978.60 : x
2. Step 2: Convert to fraction form
   6,139.98/9,210.81 = 1,978.60/x
3. Step 3: Cross multiply
   6,139.98x = 9,210.81 × 1,978.60
4. Step 4: Simplify right side
   6,139.98x = 18,224,508.67
5. Step 5: Solve for x
   x = 18,224,508.67/6,139.98
6. Step 6: Final answer
   x = 2,968.17