Finding the Fourth Proportional to 2,665.56, 3,998.67 and 1,431.28

Step by Step Solution

1. Step 1: Write the proportion equation
   2,665.56 : 3,998.67 = 1,431.28 : x
2. Step 2: Convert to fraction form
   2,665.56/3,998.67 = 1,431.28/x
3. Step 3: Cross multiply
   2,665.56x = 3,998.67 × 1,431.28
4. Step 4: Simplify right side
   2,665.56x = 5,723,189.25
5. Step 5: Solve for x
   x = 5,723,189.25/2,665.56
6. Step 6: Final answer
   x = 2,147.09