Finding the Fourth Proportional to 1,238.33, 1,708.85 and 678.83

Step by Step Solution

1. Step 1: Write the proportion equation
   1,238.33 : 1,708.85 = 678.83 : x
2. Step 2: Convert to fraction form
   1,238.33/1,708.85 = 678.83/x
3. Step 3: Cross multiply
   1,238.33x = 1,708.85 × 678.83
4. Step 4: Simplify right side
   1,238.33x = 1,160,011.80
5. Step 5: Solve for x
   x = 1,160,011.80/1,238.33
6. Step 6: Final answer
   x = 936.75