Finding the Fourth Proportional to 1,238.33, 1,708.89 and 678.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,238.33 : 1,708.89 = 678.80 : x
2. Step 2: Convert to fraction form
   1,238.33/1,708.89 = 678.80/x
3. Step 3: Cross multiply
   1,238.33x = 1,708.89 × 678.80
4. Step 4: Simplify right side
   1,238.33x = 1,159,994.53
5. Step 5: Solve for x
   x = 1,159,994.53/1,238.33
6. Step 6: Final answer
   x = 936.74