Finding the Fourth Proportional to 2,384.20, 3,290.42 and 1,389.40

Step by Step Solution

1. Step 1: Write the proportion equation
   2,384.20 : 3,290.42 = 1,389.40 : x
2. Step 2: Convert to fraction form
   2,384.20/3,290.42 = 1,389.40/x
3. Step 3: Cross multiply
   2,384.20x = 3,290.42 × 1,389.40
4. Step 4: Simplify right side
   2,384.20x = 4,571,709.55
5. Step 5: Solve for x
   x = 4,571,709.55/2,384.20
6. Step 6: Final answer
   x = 1,917.50