Finding the Fourth Proportional to 2,641.55, 3,953.21 and 2,120.31

Step by Step Solution

1. Step 1: Write the proportion equation
   2,641.55 : 3,953.21 = 2,120.31 : x
2. Step 2: Convert to fraction form
   2,641.55/3,953.21 = 2,120.31/x
3. Step 3: Cross multiply
   2,641.55x = 3,953.21 × 2,120.31
4. Step 4: Simplify right side
   2,641.55x = 8,382,020.09
5. Step 5: Solve for x
   x = 8,382,020.09/2,641.55
6. Step 6: Final answer
   x = 3,173.15