Finding the Fourth Proportional to 1,238.98, 1,858.72 and 508.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,238.98 : 1,858.72 = 508.61 : x
2. Step 2: Convert to fraction form
   1,238.98/1,858.72 = 508.61/x
3. Step 3: Cross multiply
   1,238.98x = 1,858.72 × 508.61
4. Step 4: Simplify right side
   1,238.98x = 945,363.58
5. Step 5: Solve for x
   x = 945,363.58/1,238.98
6. Step 6: Final answer
   x = 763.02