Finding the Fourth Proportional to 1,397.91, 1,928.78 and 808.46

Step by Step Solution

1. Step 1: Write the proportion equation
   1,397.91 : 1,928.78 = 808.46 : x
2. Step 2: Convert to fraction form
   1,397.91/1,928.78 = 808.46/x
3. Step 3: Cross multiply
   1,397.91x = 1,928.78 × 808.46
4. Step 4: Simplify right side
   1,397.91x = 1,559,327.79
5. Step 5: Solve for x
   x = 1,559,327.79/1,397.91
6. Step 6: Final answer
   x = 1,115.47