Finding the Fourth Proportional to 12,099.78, 16,686.61 and 7,846.40

Step by Step Solution

1. Step 1: Write the proportion equation
   12,099.78 : 16,686.61 = 7,846.40 : x
2. Step 2: Convert to fraction form
   12,099.78/16,686.61 = 7,846.40/x
3. Step 3: Cross multiply
   12,099.78x = 16,686.61 × 7,846.40
4. Step 4: Simplify right side
   12,099.78x = 130,929,838.80
5. Step 5: Solve for x
   x = 130,929,838.80/12,099.78
6. Step 6: Final answer
   x = 10,820.84