Finding the Fourth Proportional to 1,391.46, 1,918.40 and 1,155.62

Step by Step Solution

1. Step 1: Write the proportion equation
   1,391.46 : 1,918.40 = 1,155.62 : x
2. Step 2: Convert to fraction form
   1,391.46/1,918.40 = 1,155.62/x
3. Step 3: Cross multiply
   1,391.46x = 1,918.40 × 1,155.62
4. Step 4: Simplify right side
   1,391.46x = 2,216,926.04
5. Step 5: Solve for x
   x = 2,216,926.04/1,391.46
6. Step 6: Final answer
   x = 1,593.24