Finding the Fourth Proportional to 12,978.05, 19,469.50 and 4,210.61

Step by Step Solution

1. Step 1: Write the proportion equation
   12,978.05 : 19,469.50 = 4,210.61 : x
2. Step 2: Convert to fraction form
   12,978.05/19,469.50 = 4,210.61/x
3. Step 3: Cross multiply
   12,978.05x = 19,469.50 × 4,210.61
4. Step 4: Simplify right side
   12,978.05x = 81,978,363.52
5. Step 5: Solve for x
   x = 81,978,363.52/12,978.05
6. Step 6: Final answer
   x = 6,316.70