Finding the Fourth Proportional to 1,382.31, 1,906.34 and 915.75

Step by Step Solution

1. Step 1: Write the proportion equation
   1,382.31 : 1,906.34 = 915.75 : x
2. Step 2: Convert to fraction form
   1,382.31/1,906.34 = 915.75/x
3. Step 3: Cross multiply
   1,382.31x = 1,906.34 × 915.75
4. Step 4: Simplify right side
   1,382.31x = 1,745,726.28
5. Step 5: Solve for x
   x = 1,745,726.28/1,382.31
6. Step 6: Final answer
   x = 1,262.91