Finding the Fourth Proportional to 3,890.43, 5,836.79 and 1,257.89

Step by Step Solution

1. Step 1: Write the proportion equation
   3,890.43 : 5,836.79 = 1,257.89 : x
2. Step 2: Convert to fraction form
   3,890.43/5,836.79 = 1,257.89/x
3. Step 3: Cross multiply
   3,890.43x = 5,836.79 × 1,257.89
4. Step 4: Simplify right side
   3,890.43x = 7,342,004.30
5. Step 5: Solve for x
   x = 7,342,004.30/3,890.43
6. Step 6: Final answer
   x = 1,887.20