Finding the Fourth Proportional to 1,387.86, 1,915.32 and 798.18

Step by Step Solution

1. Step 1: Write the proportion equation
   1,387.86 : 1,915.32 = 798.18 : x
2. Step 2: Convert to fraction form
   1,387.86/1,915.32 = 798.18/x
3. Step 3: Cross multiply
   1,387.86x = 1,915.32 × 798.18
4. Step 4: Simplify right side
   1,387.86x = 1,528,770.12
5. Step 5: Solve for x
   x = 1,528,770.12/1,387.86
6. Step 6: Final answer
   x = 1,101.53