Finding the Fourth Proportional to 21,930.13, 30,261.23 and 12,978.01

Step by Step Solution

1. Step 1: Write the proportion equation
   21,930.13 : 30,261.23 = 12,978.01 : x
2. Step 2: Convert to fraction form
   21,930.13/30,261.23 = 12,978.01/x
3. Step 3: Cross multiply
   21,930.13x = 30,261.23 × 12,978.01
4. Step 4: Simplify right side
   21,930.13x = 392,730,545.55
5. Step 5: Solve for x
   x = 392,730,545.55/21,930.13
6. Step 6: Final answer
   x = 17,908.26