Finding the Fourth Proportional to 9,320.80, 12,862.71 and 5,129.05

Step by Step Solution

1. Step 1: Write the proportion equation
   9,320.80 : 12,862.71 = 5,129.05 : x
2. Step 2: Convert to fraction form
   9,320.80/12,862.71 = 5,129.05/x
3. Step 3: Cross multiply
   9,320.80x = 12,862.71 × 5,129.05
4. Step 4: Simplify right side
   9,320.80x = 65,973,478.35
5. Step 5: Solve for x
   x = 65,973,478.35/9,320.80
6. Step 6: Final answer
   x = 7,078.09