Finding the Fourth Proportional to 2,665.89, 3,999.99 and 1,431.86

Step by Step Solution

1. Step 1: Write the proportion equation
   2,665.89 : 3,999.99 = 1,431.86 : x
2. Step 2: Convert to fraction form
   2,665.89/3,999.99 = 1,431.86/x
3. Step 3: Cross multiply
   2,665.89x = 3,999.99 × 1,431.86
4. Step 4: Simplify right side
   2,665.89x = 5,727,425.68
5. Step 5: Solve for x
   x = 5,727,425.68/2,665.89
6. Step 6: Final answer
   x = 2,148.41