Finding the Fourth Proportional to 1,404.89, 1,938.60 and 815.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,404.89 : 1,938.60 = 815.55 : x
2. Step 2: Convert to fraction form
   1,404.89/1,938.60 = 815.55/x
3. Step 3: Cross multiply
   1,404.89x = 1,938.60 × 815.55
4. Step 4: Simplify right side
   1,404.89x = 1,581,017.96
5. Step 5: Solve for x
   x = 1,581,017.96/1,404.89
6. Step 6: Final answer
   x = 1,125.37