Finding the Fourth Proportional to 3,921.69, 5,411.88 and 2,153.31

Step by Step Solution

1. Step 1: Write the proportion equation
   3,921.69 : 5,411.88 = 2,153.31 : x
2. Step 2: Convert to fraction form
   3,921.69/5,411.88 = 2,153.31/x
3. Step 3: Cross multiply
   3,921.69x = 5,411.88 × 2,153.31
4. Step 4: Simplify right side
   3,921.69x = 11,653,455.32
5. Step 5: Solve for x
   x = 11,653,455.32/3,921.69
6. Step 6: Final answer
   x = 2,971.54