Finding the Fourth Proportional to 1,391.37, 1,920.30 and 867.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,391.37 : 1,920.30 = 867.57 : x
2. Step 2: Convert to fraction form
   1,391.37/1,920.30 = 867.57/x
3. Step 3: Cross multiply
   1,391.37x = 1,920.30 × 867.57
4. Step 4: Simplify right side
   1,391.37x = 1,665,994.67
5. Step 5: Solve for x
   x = 1,665,994.67/1,391.37
6. Step 6: Final answer
   x = 1,197.38