Finding the Fourth Proportional to 12,906.11, 17,815.89 and 8,720.03

Step by Step Solution

1. Step 1: Write the proportion equation
   12,906.11 : 17,815.89 = 8,720.03 : x
2. Step 2: Convert to fraction form
   12,906.11/17,815.89 = 8,720.03/x
3. Step 3: Cross multiply
   12,906.11x = 17,815.89 × 8,720.03
4. Step 4: Simplify right side
   12,906.11x = 155,355,095.28
5. Step 5: Solve for x
   x = 155,355,095.28/12,906.11
6. Step 6: Final answer
   x = 12,037.33