Finding the Fourth Proportional to 1,387.89, 1,915.26 and 798.39

Step by Step Solution

1. Step 1: Write the proportion equation
   1,387.89 : 1,915.26 = 798.39 : x
2. Step 2: Convert to fraction form
   1,387.89/1,915.26 = 798.39/x
3. Step 3: Cross multiply
   1,387.89x = 1,915.26 × 798.39
4. Step 4: Simplify right side
   1,387.89x = 1,529,124.43
5. Step 5: Solve for x
   x = 1,529,124.43/1,387.89
6. Step 6: Final answer
   x = 1,101.76