Finding the Fourth Proportional to 1,391.16, 1,922.54 and 1,158.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,391.16 : 1,922.54 = 1,158.20 : x
2. Step 2: Convert to fraction form
   1,391.16/1,922.54 = 1,158.20/x
3. Step 3: Cross multiply
   1,391.16x = 1,922.54 × 1,158.20
4. Step 4: Simplify right side
   1,391.16x = 2,226,685.83
5. Step 5: Solve for x
   x = 2,226,685.83/1,391.16
6. Step 6: Final answer
   x = 1,600.60