Finding the Fourth Proportional to 8,906.02, 12,291.58 and 5,128.80

Step by Step Solution

1. Step 1: Write the proportion equation
   8,906.02 : 12,291.58 = 5,128.80 : x
2. Step 2: Convert to fraction form
   8,906.02/12,291.58 = 5,128.80/x
3. Step 3: Cross multiply
   8,906.02x = 12,291.58 × 5,128.80
4. Step 4: Simplify right side
   8,906.02x = 63,041,055.50
5. Step 5: Solve for x
   x = 63,041,055.50/8,906.02
6. Step 6: Final answer
   x = 7,078.48