Finding the Fourth Proportional to 128,998.72, 178,004.56 and 72,416.32

Step by Step Solution

1. Step 1: Write the proportion equation
   128,998.72 : 178,004.56 = 72,416.32 : x
2. Step 2: Convert to fraction form
   128,998.72/178,004.56 = 72,416.32/x
3. Step 3: Cross multiply
   128,998.72x = 178,004.56 × 72,416.32
4. Step 4: Simplify right side
   128,998.72x = 12,890,435,178.42
5. Step 5: Solve for x
   x = 12,890,435,178.42/128,998.72
6. Step 6: Final answer
   x = 99,926.85