Finding the Fourth Proportional to 1,399.49, 1,930.91 and 809.99

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.49 : 1,930.91 = 809.99 : x
2. Step 2: Convert to fraction form
   1,399.49/1,930.91 = 809.99/x
3. Step 3: Cross multiply
   1,399.49x = 1,930.91 × 809.99
4. Step 4: Simplify right side
   1,399.49x = 1,564,004.09
5. Step 5: Solve for x
   x = 1,564,004.09/1,399.49
6. Step 6: Final answer
   x = 1,117.56