Finding the Fourth Proportional to 128,828.34, 177,784.47 and 72,238.50

Step by Step Solution

1. Step 1: Write the proportion equation
   128,828.34 : 177,784.47 = 72,238.50 : x
2. Step 2: Convert to fraction form
   128,828.34/177,784.47 = 72,238.50/x
3. Step 3: Cross multiply
   128,828.34x = 177,784.47 × 72,238.50
4. Step 4: Simplify right side
   128,828.34x = 12,842,883,436.10
5. Step 5: Solve for x
   x = 12,842,883,436.10/128,828.34
6. Step 6: Final answer
   x = 99,689.89