Finding the Fourth Proportional to 2,385.20, 3,291.54 and 1,390.52

Step by Step Solution

1. Step 1: Write the proportion equation
   2,385.20 : 3,291.54 = 1,390.52 : x
2. Step 2: Convert to fraction form
   2,385.20/3,291.54 = 1,390.52/x
3. Step 3: Cross multiply
   2,385.20x = 3,291.54 × 1,390.52
4. Step 4: Simplify right side
   2,385.20x = 4,576,952.20
5. Step 5: Solve for x
   x = 4,576,952.20/2,385.20
6. Step 6: Final answer
   x = 1,918.90