Finding the Fourth Proportional to 3,899.37, 5,381.33 and 2,131.05

Step by Step Solution

1. Step 1: Write the proportion equation
   3,899.37 : 5,381.33 = 2,131.05 : x
2. Step 2: Convert to fraction form
   3,899.37/5,381.33 = 2,131.05/x
3. Step 3: Cross multiply
   3,899.37x = 5,381.33 × 2,131.05
4. Step 4: Simplify right side
   3,899.37x = 11,467,883.30
5. Step 5: Solve for x
   x = 11,467,883.30/3,899.37
6. Step 6: Final answer
   x = 2,940.96