Finding the Fourth Proportional to 1,405.47, 1,939.89 and 815.92

Step by Step Solution

1. Step 1: Write the proportion equation
   1,405.47 : 1,939.89 = 815.92 : x
2. Step 2: Convert to fraction form
   1,405.47/1,939.89 = 815.92/x
3. Step 3: Cross multiply
   1,405.47x = 1,939.89 × 815.92
4. Step 4: Simplify right side
   1,405.47x = 1,582,795.05
5. Step 5: Solve for x
   x = 1,582,795.05/1,405.47
6. Step 6: Final answer
   x = 1,126.17