Finding the Fourth Proportional to 128,856.42, 177,821.33 and 72,267.80

Step by Step Solution

1. Step 1: Write the proportion equation
   128,856.42 : 177,821.33 = 72,267.80 : x
2. Step 2: Convert to fraction form
   128,856.42/177,821.33 = 72,267.80/x
3. Step 3: Cross multiply
   128,856.42x = 177,821.33 × 72,267.80
4. Step 4: Simplify right side
   128,856.42x = 12,850,755,061.73
5. Step 5: Solve for x
   x = 12,850,755,061.73/128,856.42
6. Step 6: Final answer
   x = 99,729.26