Finding the Fourth Proportional to 12,858.72, 17,712.72 and 12,858.72

Step by Step Solution

1. Step 1: Write the proportion equation
   12,858.72 : 17,712.72 = 12,858.72 : x
2. Step 2: Convert to fraction form
   12,858.72/17,712.72 = 12,858.72/x
3. Step 3: Cross multiply
   12,858.72x = 17,712.72 × 12,858.72
4. Step 4: Simplify right side
   12,858.72x = 227,762,906.92
5. Step 5: Solve for x
   x = 227,762,906.92/12,858.72
6. Step 6: Final answer
   x = 17,712.72