Finding the Fourth Proportional to 8,139.78, 12,210.14 and 3,142.18

Step by Step Solution

1. Step 1: Write the proportion equation
   8,139.78 : 12,210.14 = 3,142.18 : x
2. Step 2: Convert to fraction form
   8,139.78/12,210.14 = 3,142.18/x
3. Step 3: Cross multiply
   8,139.78x = 12,210.14 × 3,142.18
4. Step 4: Simplify right side
   8,139.78x = 38,366,457.71
5. Step 5: Solve for x
   x = 38,366,457.71/8,139.78
6. Step 6: Final answer
   x = 4,713.45