Finding the Fourth Proportional to 1,009.42, 1,391.52 and 787.90

Step by Step Solution

1. Step 1: Write the proportion equation
   1,009.42 : 1,391.52 = 787.90 : x
2. Step 2: Convert to fraction form
   1,009.42/1,391.52 = 787.90/x
3. Step 3: Cross multiply
   1,009.42x = 1,391.52 × 787.90
4. Step 4: Simplify right side
   1,009.42x = 1,096,378.61
5. Step 5: Solve for x
   x = 1,096,378.61/1,009.42
6. Step 6: Final answer
   x = 1,086.15