Finding the Fourth Proportional to 8,760.78, 12,090.06 and 5,405.22

Step by Step Solution

1. Step 1: Write the proportion equation
   8,760.78 : 12,090.06 = 5,405.22 : x
2. Step 2: Convert to fraction form
   8,760.78/12,090.06 = 5,405.22/x
3. Step 3: Cross multiply
   8,760.78x = 12,090.06 × 5,405.22
4. Step 4: Simplify right side
   8,760.78x = 65,349,434.11
5. Step 5: Solve for x
   x = 65,349,434.11/8,760.78
6. Step 6: Final answer
   x = 7,459.32