Finding the Fourth Proportional to 128,938.56, 177,938.28 and 72,354.12

Step by Step Solution

1. Step 1: Write the proportion equation
   128,938.56 : 177,938.28 = 72,354.12 : x
2. Step 2: Convert to fraction form
   128,938.56/177,938.28 = 72,354.12/x
3. Step 3: Cross multiply
   128,938.56x = 177,938.28 × 72,354.12
4. Step 4: Simplify right side
   128,938.56x = 12,874,567,663.71
5. Step 5: Solve for x
   x = 12,874,567,663.71/128,938.56
6. Step 6: Final answer
   x = 99,850.41