Finding the Fourth Proportional to 1,397.57, 1,928.49 and 808.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,397.57 : 1,928.49 = 808.31 : x
2. Step 2: Convert to fraction form
   1,397.57/1,928.49 = 808.31/x
3. Step 3: Cross multiply
   1,397.57x = 1,928.49 × 808.31
4. Step 4: Simplify right side
   1,397.57x = 1,558,817.75
5. Step 5: Solve for x
   x = 1,558,817.75/1,397.57
6. Step 6: Final answer
   x = 1,115.38