Finding the Fourth Proportional to 1,405.05, 1,938.90 and 815.49

Step by Step Solution

1. Step 1: Write the proportion equation
   1,405.05 : 1,938.90 = 815.49 : x
2. Step 2: Convert to fraction form
   1,405.05/1,938.90 = 815.49/x
3. Step 3: Cross multiply
   1,405.05x = 1,938.90 × 815.49
4. Step 4: Simplify right side
   1,405.05x = 1,581,153.56
5. Step 5: Solve for x
   x = 1,581,153.56/1,405.05
6. Step 6: Final answer
   x = 1,125.34