Finding the Fourth Proportional to 208,862.72, 288,380.34 and 128,398.12

Step by Step Solution

1. Step 1: Write the proportion equation
   208,862.72 : 288,380.34 = 128,398.12 : x
2. Step 2: Convert to fraction form
   208,862.72/288,380.34 = 128,398.12/x
3. Step 3: Cross multiply
   208,862.72x = 288,380.34 × 128,398.12
4. Step 4: Simplify right side
   208,862.72x = 37,027,493,500.96
5. Step 5: Solve for x
   x = 37,027,493,500.96/208,862.72
6. Step 6: Final answer
   x = 177,281.49