Finding the Fourth Proportional to 3,978.76, 5,451.29 and 3,831.34

Step by Step Solution

1. Step 1: Write the proportion equation
   3,978.76 : 5,451.29 = 3,831.34 : x
2. Step 2: Convert to fraction form
   3,978.76/5,451.29 = 3,831.34/x
3. Step 3: Cross multiply
   3,978.76x = 5,451.29 × 3,831.34
4. Step 4: Simplify right side
   3,978.76x = 20,885,745.43
5. Step 5: Solve for x
   x = 20,885,745.43/3,978.76
6. Step 6: Final answer
   x = 5,249.31