Finding the Fourth Proportional to 1,397.40, 1,929.31 and 866.85

Step by Step Solution

1. Step 1: Write the proportion equation
   1,397.40 : 1,929.31 = 866.85 : x
2. Step 2: Convert to fraction form
   1,397.40/1,929.31 = 866.85/x
3. Step 3: Cross multiply
   1,397.40x = 1,929.31 × 866.85
4. Step 4: Simplify right side
   1,397.40x = 1,672,412.73
5. Step 5: Solve for x
   x = 1,672,412.73/1,397.40
6. Step 6: Final answer
   x = 1,196.81