Finding the Fourth Proportional to 12,864.16, 17,755.31 and 7,830

Step by Step Solution

1. Step 1: Write the proportion equation
   12,864.16 : 17,755.31 = 7,830 : x
2. Step 2: Convert to fraction form
   12,864.16/17,755.31 = 7,830/x
3. Step 3: Cross multiply
   12,864.16x = 17,755.31 × 7,830
4. Step 4: Simplify right side
   12,864.16x = 139,024,077.30
5. Step 5: Solve for x
   x = 139,024,077.30/12,864.16
6. Step 6: Final answer
   x = 10,807.09