Finding the Fourth Proportional to 12,978.10, 19,481.55 and 12,132.10

Step by Step Solution

1. Step 1: Write the proportion equation
   12,978.10 : 19,481.55 = 12,132.10 : x
2. Step 2: Convert to fraction form
   12,978.10/19,481.55 = 12,132.10/x
3. Step 3: Cross multiply
   12,978.10x = 19,481.55 × 12,132.10
4. Step 4: Simplify right side
   12,978.10x = 236,352,112.76
5. Step 5: Solve for x
   x = 236,352,112.76/12,978.10
6. Step 6: Final answer
   x = 18,211.61