Finding the Fourth Proportional to 1,387.98, 1,915.41 and 798.47

Step by Step Solution

1. Step 1: Write the proportion equation
   1,387.98 : 1,915.41 = 798.47 : x
2. Step 2: Convert to fraction form
   1,387.98/1,915.41 = 798.47/x
3. Step 3: Cross multiply
   1,387.98x = 1,915.41 × 798.47
4. Step 4: Simplify right side
   1,387.98x = 1,529,393.43
5. Step 5: Solve for x
   x = 1,529,393.43/1,387.98
6. Step 6: Final answer
   x = 1,101.89