Finding the Fourth Proportional to 1,399.45, 1,930.71 and 809.77

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.45 : 1,930.71 = 809.77 : x
2. Step 2: Convert to fraction form
   1,399.45/1,930.71 = 809.77/x
3. Step 3: Cross multiply
   1,399.45x = 1,930.71 × 809.77
4. Step 4: Simplify right side
   1,399.45x = 1,563,431.04
5. Step 5: Solve for x
   x = 1,563,431.04/1,399.45
6. Step 6: Final answer
   x = 1,117.18