Finding the Fourth Proportional to 1,223.34, 1,688.23 and 663.83

Step by Step Solution

1. Step 1: Write the proportion equation
   1,223.34 : 1,688.23 = 663.83 : x
2. Step 2: Convert to fraction form
   1,223.34/1,688.23 = 663.83/x
3. Step 3: Cross multiply
   1,223.34x = 1,688.23 × 663.83
4. Step 4: Simplify right side
   1,223.34x = 1,120,697.72
5. Step 5: Solve for x
   x = 1,120,697.72/1,223.34
6. Step 6: Final answer
   x = 916.10