Finding the Fourth Proportional to 1,399.35, 1,930.98 and 809.93

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.35 : 1,930.98 = 809.93 : x
2. Step 2: Convert to fraction form
   1,399.35/1,930.98 = 809.93/x
3. Step 3: Cross multiply
   1,399.35x = 1,930.98 × 809.93
4. Step 4: Simplify right side
   1,399.35x = 1,563,948.98
5. Step 5: Solve for x
   x = 1,563,948.98/1,399.35
6. Step 6: Final answer
   x = 1,117.63