Finding the Fourth Proportional to 21,076.86, 29,076.93 and 12,688.50

Step by Step Solution

1. Step 1: Write the proportion equation
   21,076.86 : 29,076.93 = 12,688.50 : x
2. Step 2: Convert to fraction form
   21,076.86/29,076.93 = 12,688.50/x
3. Step 3: Cross multiply
   21,076.86x = 29,076.93 × 12,688.50
4. Step 4: Simplify right side
   21,076.86x = 368,942,626.31
5. Step 5: Solve for x
   x = 368,942,626.31/21,076.86
6. Step 6: Final answer
   x = 17,504.63