Finding the Fourth Proportional to 128,760.84, 177,691.32 and 72,171

Step by Step Solution

1. Step 1: Write the proportion equation
   128,760.84 : 177,691.32 = 72,171 : x
2. Step 2: Convert to fraction form
   128,760.84/177,691.32 = 72,171/x
3. Step 3: Cross multiply
   128,760.84x = 177,691.32 × 72,171
4. Step 4: Simplify right side
   128,760.84x = 12,824,160,255.72
5. Step 5: Solve for x
   x = 12,824,160,255.72/128,760.84
6. Step 6: Final answer
   x = 99,596.74