Finding the Fourth Proportional to 2,385.18, 3,291.17 and 1,390.50

Step by Step Solution

1. Step 1: Write the proportion equation
   2,385.18 : 3,291.17 = 1,390.50 : x
2. Step 2: Convert to fraction form
   2,385.18/3,291.17 = 1,390.50/x
3. Step 3: Cross multiply
   2,385.18x = 3,291.17 × 1,390.50
4. Step 4: Simplify right side
   2,385.18x = 4,576,364.93
5. Step 5: Solve for x
   x = 4,576,364.93/2,385.18
6. Step 6: Final answer
   x = 1,918.67