Finding the Fourth Proportional to 2,665.21, 3,998.96 and 1,431.18

Step by Step Solution

1. Step 1: Write the proportion equation
   2,665.21 : 3,998.96 = 1,431.18 : x
2. Step 2: Convert to fraction form
   2,665.21/3,998.96 = 1,431.18/x
3. Step 3: Cross multiply
   2,665.21x = 3,998.96 × 1,431.18
4. Step 4: Simplify right side
   2,665.21x = 5,723,211.58
5. Step 5: Solve for x
   x = 5,723,211.58/2,665.21
6. Step 6: Final answer
   x = 2,147.38