Finding the Fourth Proportional to 1,390.37, 1,918.89 and 801.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.37 : 1,918.89 = 801.09 : x
2. Step 2: Convert to fraction form
   1,390.37/1,918.89 = 801.09/x
3. Step 3: Cross multiply
   1,390.37x = 1,918.89 × 801.09
4. Step 4: Simplify right side
   1,390.37x = 1,537,203.59
5. Step 5: Solve for x
   x = 1,537,203.59/1,390.37
6. Step 6: Final answer
   x = 1,105.61