Finding the Fourth Proportional to 1,238.24, 1,857.12 and 458.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,238.24 : 1,857.12 = 458.72 : x
2. Step 2: Convert to fraction form
   1,238.24/1,857.12 = 458.72/x
3. Step 3: Cross multiply
   1,238.24x = 1,857.12 × 458.72
4. Step 4: Simplify right side
   1,238.24x = 851,898.09
5. Step 5: Solve for x
   x = 851,898.09/1,238.24
6. Step 6: Final answer
   x = 687.99