Finding the Fourth Proportional to 128,926.56, 177,921.72 and 72,342.12

Step by Step Solution

1. Step 1: Write the proportion equation
   128,926.56 : 177,921.72 = 72,342.12 : x
2. Step 2: Convert to fraction form
   128,926.56/177,921.72 = 72,342.12/x
3. Step 3: Cross multiply
   128,926.56x = 177,921.72 × 72,342.12
4. Step 4: Simplify right side
   128,926.56x = 12,871,234,418.85
5. Step 5: Solve for x
   x = 12,871,234,418.85/128,926.56
6. Step 6: Final answer
   x = 99,833.85