Finding the Fourth Proportional to 1,224.38, 1,689.61 and 664.83

Step by Step Solution

1. Step 1: Write the proportion equation
   1,224.38 : 1,689.61 = 664.83 : x
2. Step 2: Convert to fraction form
   1,224.38/1,689.61 = 664.83/x
3. Step 3: Cross multiply
   1,224.38x = 1,689.61 × 664.83
4. Step 4: Simplify right side
   1,224.38x = 1,123,303.42
5. Step 5: Solve for x
   x = 1,123,303.42/1,224.38
6. Step 6: Final answer
   x = 917.45