Finding the Fourth Proportional to 2,385.39, 3,291.83 and 1,390.47

Step by Step Solution

1. Step 1: Write the proportion equation
   2,385.39 : 3,291.83 = 1,390.47 : x
2. Step 2: Convert to fraction form
   2,385.39/3,291.83 = 1,390.47/x
3. Step 3: Cross multiply
   2,385.39x = 3,291.83 × 1,390.47
4. Step 4: Simplify right side
   2,385.39x = 4,577,204.45
5. Step 5: Solve for x
   x = 4,577,204.45/2,385.39
6. Step 6: Final answer
   x = 1,918.85