Finding the Fourth Proportional to 1,391.50, 2,086.82 and 916.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,391.50 : 2,086.82 = 916.56 : x
2. Step 2: Convert to fraction form
   1,391.50/2,086.82 = 916.56/x
3. Step 3: Cross multiply
   1,391.50x = 2,086.82 × 916.56
4. Step 4: Simplify right side
   1,391.50x = 1,912,698.03
5. Step 5: Solve for x
   x = 1,912,698.03/1,391.50
6. Step 6: Final answer
   x = 1,374.56