Finding the Fourth Proportional to 1,223.62, 1,688.59 and 677.91

Step by Step Solution

1. Step 1: Write the proportion equation
   1,223.62 : 1,688.59 = 677.91 : x
2. Step 2: Convert to fraction form
   1,223.62/1,688.59 = 677.91/x
3. Step 3: Cross multiply
   1,223.62x = 1,688.59 × 677.91
4. Step 4: Simplify right side
   1,223.62x = 1,144,712.05
5. Step 5: Solve for x
   x = 1,144,712.05/1,223.62
6. Step 6: Final answer
   x = 935.51