Finding the Fourth Proportional to 1,398.63, 1,930.05 and 809.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.63 : 1,930.05 = 809.10 : x
2. Step 2: Convert to fraction form
   1,398.63/1,930.05 = 809.10/x
3. Step 3: Cross multiply
   1,398.63x = 1,930.05 × 809.10
4. Step 4: Simplify right side
   1,398.63x = 1,561,603.46
5. Step 5: Solve for x
   x = 1,561,603.46/1,398.63
6. Step 6: Final answer
   x = 1,116.52