Finding the Fourth Proportional to 1,405.18, 1,938.82 and 815.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,405.18 : 1,938.82 = 815.61 : x
2. Step 2: Convert to fraction form
   1,405.18/1,938.82 = 815.61/x
3. Step 3: Cross multiply
   1,405.18x = 1,938.82 × 815.61
4. Step 4: Simplify right side
   1,405.18x = 1,581,320.98
5. Step 5: Solve for x
   x = 1,581,320.98/1,405.18
6. Step 6: Final answer
   x = 1,125.35