Finding the Fourth Proportional to 7,129.68, 10,683.24 and 5,172.72

Step by Step Solution

1. Step 1: Write the proportion equation
   7,129.68 : 10,683.24 = 5,172.72 : x
2. Step 2: Convert to fraction form
   7,129.68/10,683.24 = 5,172.72/x
3. Step 3: Cross multiply
   7,129.68x = 10,683.24 × 5,172.72
4. Step 4: Simplify right side
   7,129.68x = 55,261,409.21
5. Step 5: Solve for x
   x = 55,261,409.21/7,129.68
6. Step 6: Final answer
   x = 7,750.90