Finding the Fourth Proportional to 128,469, 177,287.22 and 71,891.31

Step by Step Solution

1. Step 1: Write the proportion equation
   128,469 : 177,287.22 = 71,891.31 : x
2. Step 2: Convert to fraction form
   128,469/177,287.22 = 71,891.31/x
3. Step 3: Cross multiply
   128,469x = 177,287.22 × 71,891.31
4. Step 4: Simplify right side
   128,469x = 12,745,410,492.06
5. Step 5: Solve for x
   x = 12,745,410,492.06/128,469
6. Step 6: Final answer
   x = 99,210.01