Finding the Fourth Proportional to 1,387.92, 1,915.61 and 798.86

Step by Step Solution

1. Step 1: Write the proportion equation
   1,387.92 : 1,915.61 = 798.86 : x
2. Step 2: Convert to fraction form
   1,387.92/1,915.61 = 798.86/x
3. Step 3: Cross multiply
   1,387.92x = 1,915.61 × 798.86
4. Step 4: Simplify right side
   1,387.92x = 1,530,304.20
5. Step 5: Solve for x
   x = 1,530,304.20/1,387.92
6. Step 6: Final answer
   x = 1,102.59