Finding the Fourth Proportional to 1,223.48, 1,688.76 and 699.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,223.48 : 1,688.76 = 699.56 : x
2. Step 2: Convert to fraction form
   1,223.48/1,688.76 = 699.56/x
3. Step 3: Cross multiply
   1,223.48x = 1,688.76 × 699.56
4. Step 4: Simplify right side
   1,223.48x = 1,181,388.95
5. Step 5: Solve for x
   x = 1,181,388.95/1,223.48
6. Step 6: Final answer
   x = 965.60