Finding the Fourth Proportional to 12,978.55, 19,470.25 and 4,211.11

Step by Step Solution

1. Step 1: Write the proportion equation
   12,978.55 : 19,470.25 = 4,211.11 : x
2. Step 2: Convert to fraction form
   12,978.55/19,470.25 = 4,211.11/x
3. Step 3: Cross multiply
   12,978.55x = 19,470.25 × 4,211.11
4. Step 4: Simplify right side
   12,978.55x = 81,991,267.13
5. Step 5: Solve for x
   x = 81,991,267.13/12,978.55
6. Step 6: Final answer
   x = 6,317.45