Finding the Fourth Proportional to 1,392.57, 1,919.88 and 1,155.65

Step by Step Solution

1. Step 1: Write the proportion equation
   1,392.57 : 1,919.88 = 1,155.65 : x
2. Step 2: Convert to fraction form
   1,392.57/1,919.88 = 1,155.65/x
3. Step 3: Cross multiply
   1,392.57x = 1,919.88 × 1,155.65
4. Step 4: Simplify right side
   1,392.57x = 2,218,699.72
5. Step 5: Solve for x
   x = 2,218,699.72/1,392.57
6. Step 6: Final answer
   x = 1,593.24