Finding the Fourth Proportional to 12,978.78, 19,461.20 and 4,092.45

Step by Step Solution

1. Step 1: Write the proportion equation
   12,978.78 : 19,461.20 = 4,092.45 : x
2. Step 2: Convert to fraction form
   12,978.78/19,461.20 = 4,092.45/x
3. Step 3: Cross multiply
   12,978.78x = 19,461.20 × 4,092.45
4. Step 4: Simplify right side
   12,978.78x = 79,643,967.48
5. Step 5: Solve for x
   x = 79,643,967.48/12,978.78
6. Step 6: Final answer
   x = 6,136.48