Finding the Fourth Proportional to 315,879.72, 435,913.25 and 172,640.78

Step by Step Solution

1. Step 1: Write the proportion equation
   315,879.72 : 435,913.25 = 172,640.78 : x
2. Step 2: Convert to fraction form
   315,879.72/435,913.25 = 172,640.78/x
3. Step 3: Cross multiply
   315,879.72x = 435,913.25 × 172,640.78
4. Step 4: Simplify right side
   315,879.72x = 75,256,404,536.25
5. Step 5: Solve for x
   x = 75,256,404,536.25/315,879.72
6. Step 6: Final answer
   x = 238,243.87