Finding the Fourth Proportional to 1,398.69, 1,930.41 and 801.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.69 : 1,930.41 = 801.20 : x
2. Step 2: Convert to fraction form
   1,398.69/1,930.41 = 801.20/x
3. Step 3: Cross multiply
   1,398.69x = 1,930.41 × 801.20
4. Step 4: Simplify right side
   1,398.69x = 1,546,649.32
5. Step 5: Solve for x
   x = 1,546,649.32/1,398.69
6. Step 6: Final answer
   x = 1,105.78