Finding the Fourth Proportional to 428,002.84, 642,111 and 128,488.96

Step by Step Solution

1. Step 1: Write the proportion equation
   428,002.84 : 642,111 = 128,488.96 : x
2. Step 2: Convert to fraction form
   428,002.84/642,111 = 128,488.96/x
3. Step 3: Cross multiply
   428,002.84x = 642,111 × 128,488.96
4. Step 4: Simplify right side
   428,002.84x = 82,504,174,594.56
5. Step 5: Solve for x
   x = 82,504,174,594.56/428,002.84
6. Step 6: Final answer
   x = 192,765.48