Finding the Fourth Proportional to 1,223.47, 1,688.43 and 699.49

Step by Step Solution

1. Step 1: Write the proportion equation
   1,223.47 : 1,688.43 = 699.49 : x
2. Step 2: Convert to fraction form
   1,223.47/1,688.43 = 699.49/x
3. Step 3: Cross multiply
   1,223.47x = 1,688.43 × 699.49
4. Step 4: Simplify right side
   1,223.47x = 1,181,039.90
5. Step 5: Solve for x
   x = 1,181,039.90/1,223.47
6. Step 6: Final answer
   x = 965.32