Finding the Fourth Proportional to 5,421.50, 8,128.31 and 3,662.15

Step by Step Solution

1. Step 1: Write the proportion equation
   5,421.50 : 8,128.31 = 3,662.15 : x
2. Step 2: Convert to fraction form
   5,421.50/8,128.31 = 3,662.15/x
3. Step 3: Cross multiply
   5,421.50x = 8,128.31 × 3,662.15
4. Step 4: Simplify right side
   5,421.50x = 29,767,058.98
5. Step 5: Solve for x
   x = 29,767,058.98/5,421.50
6. Step 6: Final answer
   x = 5,490.56