Finding the Fourth Proportional to 139,039.10, 208,510.05 and 72,457.10

Step by Step Solution

1. Step 1: Write the proportion equation
   139,039.10 : 208,510.05 = 72,457.10 : x
2. Step 2: Convert to fraction form
   139,039.10/208,510.05 = 72,457.10/x
3. Step 3: Cross multiply
   139,039.10x = 208,510.05 × 72,457.10
4. Step 4: Simplify right side
   139,039.10x = 15,108,033,543.86
5. Step 5: Solve for x
   x = 15,108,033,543.86/139,039.10
6. Step 6: Final answer
   x = 108,660.32