Finding the Fourth Proportional to 12,128.90, 18,192.78 and 3,807.62

Step by Step Solution

1. Step 1: Write the proportion equation
   12,128.90 : 18,192.78 = 3,807.62 : x
2. Step 2: Convert to fraction form
   12,128.90/18,192.78 = 3,807.62/x
3. Step 3: Cross multiply
   12,128.90x = 18,192.78 × 3,807.62
4. Step 4: Simplify right side
   12,128.90x = 69,271,192.98
5. Step 5: Solve for x
   x = 69,271,192.98/12,128.90
6. Step 6: Final answer
   x = 5,711.25