Finding the Fourth Proportional to 1,223.16, 1,687.98 and 699.18

Step by Step Solution

1. Step 1: Write the proportion equation
   1,223.16 : 1,687.98 = 699.18 : x
2. Step 2: Convert to fraction form
   1,223.16/1,687.98 = 699.18/x
3. Step 3: Cross multiply
   1,223.16x = 1,687.98 × 699.18
4. Step 4: Simplify right side
   1,223.16x = 1,180,201.86
5. Step 5: Solve for x
   x = 1,180,201.86/1,223.16
6. Step 6: Final answer
   x = 964.88