Finding the Fourth Proportional to 9,109.61, 12,574.79 and 7,120.81

Step by Step Solution

1. Step 1: Write the proportion equation
   9,109.61 : 12,574.79 = 7,120.81 : x
2. Step 2: Convert to fraction form
   9,109.61/12,574.79 = 7,120.81/x
3. Step 3: Cross multiply
   9,109.61x = 12,574.79 × 7,120.81
4. Step 4: Simplify right side
   9,109.61x = 89,542,737.25
5. Step 5: Solve for x
   x = 89,542,737.25/9,109.61
6. Step 6: Final answer
   x = 9,829.48