Finding the Fourth Proportional to 12,978.45, 17,900.46 and 11,189.07

Step by Step Solution

1. Step 1: Write the proportion equation
   12,978.45 : 17,900.46 = 11,189.07 : x
2. Step 2: Convert to fraction form
   12,978.45/17,900.46 = 11,189.07/x
3. Step 3: Cross multiply
   12,978.45x = 17,900.46 × 11,189.07
4. Step 4: Simplify right side
   12,978.45x = 200,289,499.97
5. Step 5: Solve for x
   x = 200,289,499.97/12,978.45
6. Step 6: Final answer
   x = 15,432.47