Finding the Fourth Proportional to 1,391.89, 1,920.47 and 832.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,391.89 : 1,920.47 = 832.57 : x
2. Step 2: Convert to fraction form
   1,391.89/1,920.47 = 832.57/x
3. Step 3: Cross multiply
   1,391.89x = 1,920.47 × 832.57
4. Step 4: Simplify right side
   1,391.89x = 1,598,925.71
5. Step 5: Solve for x
   x = 1,598,925.71/1,391.89
6. Step 6: Final answer
   x = 1,148.74