Finding the Fourth Proportional to 8,020.78, 12,031.61 and 3,638.57

Step by Step Solution

1. Step 1: Write the proportion equation
   8,020.78 : 12,031.61 = 3,638.57 : x
2. Step 2: Convert to fraction form
   8,020.78/12,031.61 = 3,638.57/x
3. Step 3: Cross multiply
   8,020.78x = 12,031.61 × 3,638.57
4. Step 4: Simplify right side
   8,020.78x = 43,777,776.85
5. Step 5: Solve for x
   x = 43,777,776.85/8,020.78
6. Step 6: Final answer
   x = 5,458.05