Finding the Fourth Proportional to 9,151.47, 12,628.55 and 5,172.78

Step by Step Solution

1. Step 1: Write the proportion equation
   9,151.47 : 12,628.55 = 5,172.78 : x
2. Step 2: Convert to fraction form
   9,151.47/12,628.55 = 5,172.78/x
3. Step 3: Cross multiply
   9,151.47x = 12,628.55 × 5,172.78
4. Step 4: Simplify right side
   9,151.47x = 65,324,685.01
5. Step 5: Solve for x
   x = 65,324,685.01/9,151.47
6. Step 6: Final answer
   x = 7,138.16