Finding the Fourth Proportional to 1,223.90, 1,689.10 and 699.83

Step by Step Solution

1. Step 1: Write the proportion equation
   1,223.90 : 1,689.10 = 699.83 : x
2. Step 2: Convert to fraction form
   1,223.90/1,689.10 = 699.83/x
3. Step 3: Cross multiply
   1,223.90x = 1,689.10 × 699.83
4. Step 4: Simplify right side
   1,223.90x = 1,182,079.35
5. Step 5: Solve for x
   x = 1,182,079.35/1,223.90
6. Step 6: Final answer
   x = 965.83