Finding the Fourth Proportional to 1,397.60, 1,928.56 and 808.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,397.60 : 1,928.56 = 808.12 : x
2. Step 2: Convert to fraction form
   1,397.60/1,928.56 = 808.12/x
3. Step 3: Cross multiply
   1,397.60x = 1,928.56 × 808.12
4. Step 4: Simplify right side
   1,397.60x = 1,558,507.91
5. Step 5: Solve for x
   x = 1,558,507.91/1,397.60
6. Step 6: Final answer
   x = 1,115.13