Finding the Fourth Proportional to 1,213.29, 1,818.86 and 443.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,213.29 : 1,818.86 = 443.61 : x
2. Step 2: Convert to fraction form
   1,213.29/1,818.86 = 443.61/x
3. Step 3: Cross multiply
   1,213.29x = 1,818.86 × 443.61
4. Step 4: Simplify right side
   1,213.29x = 806,862.27
5. Step 5: Solve for x
   x = 806,862.27/1,213.29
6. Step 6: Final answer
   x = 665.02