Finding the Fourth Proportional to 128,984.67, 178,001.96 and 72,401.31

Step by Step Solution

1. Step 1: Write the proportion equation
   128,984.67 : 178,001.96 = 72,401.31 : x
2. Step 2: Convert to fraction form
   128,984.67/178,001.96 = 72,401.31/x
3. Step 3: Cross multiply
   128,984.67x = 178,001.96 × 72,401.31
4. Step 4: Simplify right side
   128,984.67x = 12,887,574,724.56
5. Step 5: Solve for x
   x = 12,887,574,724.56/128,984.67
6. Step 6: Final answer
   x = 99,915.55