Finding the Fourth Proportional to 128,740.72, 177,652.42 and 72,141.16

Step by Step Solution

1. Step 1: Write the proportion equation
   128,740.72 : 177,652.42 = 72,141.16 : x
2. Step 2: Convert to fraction form
   128,740.72/177,652.42 = 72,141.16/x
3. Step 3: Cross multiply
   128,740.72x = 177,652.42 × 72,141.16
4. Step 4: Simplify right side
   128,740.72x = 12,816,051,655.61
5. Step 5: Solve for x
   x = 12,816,051,655.61/128,740.72
6. Step 6: Final answer
   x = 99,549.32