Finding the Fourth Proportional to 3,885.31, 5,361.71 and 2,116.91

Step by Step Solution

1. Step 1: Write the proportion equation
   3,885.31 : 5,361.71 = 2,116.91 : x
2. Step 2: Convert to fraction form
   3,885.31/5,361.71 = 2,116.91/x
3. Step 3: Cross multiply
   3,885.31x = 5,361.71 × 2,116.91
4. Step 4: Simplify right side
   3,885.31x = 11,350,257.52
5. Step 5: Solve for x
   x = 11,350,257.52/3,885.31
6. Step 6: Final answer
   x = 2,921.33