Finding the Fourth Proportional to 19,662.20, 29,443.04 and 12,978.48

Step by Step Solution

1. Step 1: Write the proportion equation
   19,662.20 : 29,443.04 = 12,978.48 : x
2. Step 2: Convert to fraction form
   19,662.20/29,443.04 = 12,978.48/x
3. Step 3: Cross multiply
   19,662.20x = 29,443.04 × 12,978.48
4. Step 4: Simplify right side
   19,662.20x = 382,125,905.78
5. Step 5: Solve for x
   x = 382,125,905.78/19,662.20
6. Step 6: Final answer
   x = 19,434.54