Finding the Fourth Proportional to 128,711.39, 177,613.25 and 72,111.83

Step by Step Solution

1. Step 1: Write the proportion equation
   128,711.39 : 177,613.25 = 72,111.83 : x
2. Step 2: Convert to fraction form
   128,711.39/177,613.25 = 72,111.83/x
3. Step 3: Cross multiply
   128,711.39x = 177,613.25 × 72,111.83
4. Step 4: Simplify right side
   128,711.39x = 12,808,015,241.12
5. Step 5: Solve for x
   x = 12,808,015,241.12/128,711.39
6. Step 6: Final answer
   x = 99,509.58