Finding the Fourth Proportional to 1,388.07, 1,915.55 and 798.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.07 : 1,915.55 = 798.80 : x
2. Step 2: Convert to fraction form
   1,388.07/1,915.55 = 798.80/x
3. Step 3: Cross multiply
   1,388.07x = 1,915.55 × 798.80
4. Step 4: Simplify right side
   1,388.07x = 1,530,127.77
5. Step 5: Solve for x
   x = 1,530,127.77/1,388.07
6. Step 6: Final answer
   x = 1,102.34