Finding the Fourth Proportional to 128,640.72, 177,532.38 and 72,055.56

Step by Step Solution

1. Step 1: Write the proportion equation
   128,640.72 : 177,532.38 = 72,055.56 : x
2. Step 2: Convert to fraction form
   128,640.72/177,532.38 = 72,055.56/x
3. Step 3: Cross multiply
   128,640.72x = 177,532.38 × 72,055.56
4. Step 4: Simplify right side
   128,640.72x = 12,792,195,059.03
5. Step 5: Solve for x
   x = 12,792,195,059.03/128,640.72
6. Step 6: Final answer
   x = 99,441.26