Finding the Fourth Proportional to 128,598.24, 177,468.72 and 72,021.12

Step by Step Solution

1. Step 1: Write the proportion equation
   128,598.24 : 177,468.72 = 72,021.12 : x
2. Step 2: Convert to fraction form
   128,598.24/177,468.72 = 72,021.12/x
3. Step 3: Cross multiply
   128,598.24x = 177,468.72 × 72,021.12
4. Step 4: Simplify right side
   128,598.24x = 12,781,495,979.37
5. Step 5: Solve for x
   x = 12,781,495,979.37/128,598.24
6. Step 6: Final answer
   x = 99,390.91