Finding the Fourth Proportional to 1,223.52, 1,688.42 and 699.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,223.52 : 1,688.42 = 699.50 : x
2. Step 2: Convert to fraction form
   1,223.52/1,688.42 = 699.50/x
3. Step 3: Cross multiply
   1,223.52x = 1,688.42 × 699.50
4. Step 4: Simplify right side
   1,223.52x = 1,181,049.79
5. Step 5: Solve for x
   x = 1,181,049.79/1,223.52
6. Step 6: Final answer
   x = 965.29