Finding the Fourth Proportional to 1,388.27, 1,915.83 and 798.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.27 : 1,915.83 = 798.80 : x
2. Step 2: Convert to fraction form
   1,388.27/1,915.83 = 798.80/x
3. Step 3: Cross multiply
   1,388.27x = 1,915.83 × 798.80
4. Step 4: Simplify right side
   1,388.27x = 1,530,355.42
5. Step 5: Solve for x
   x = 1,530,355.42/1,388.27
6. Step 6: Final answer
   x = 1,102.35