Finding the Fourth Proportional to 100,728.96, 139,003.05 and 55,406.94

Step by Step Solution

1. Step 1: Write the proportion equation
   100,728.96 : 139,003.05 = 55,406.94 : x
2. Step 2: Convert to fraction form
   100,728.96/139,003.05 = 55,406.94/x
3. Step 3: Cross multiply
   100,728.96x = 139,003.05 × 55,406.94
4. Step 4: Simplify right side
   100,728.96x = 7,701,733,651.17
5. Step 5: Solve for x
   x = 7,701,733,651.17/100,728.96
6. Step 6: Final answer
   x = 76,459.97