Finding the Fourth Proportional to 3,921.51, 5,411.61 and 2,153.10

Step by Step Solution

1. Step 1: Write the proportion equation
   3,921.51 : 5,411.61 = 2,153.10 : x
2. Step 2: Convert to fraction form
   3,921.51/5,411.61 = 2,153.10/x
3. Step 3: Cross multiply
   3,921.51x = 5,411.61 × 2,153.10
4. Step 4: Simplify right side
   3,921.51x = 11,651,727.34
5. Step 5: Solve for x
   x = 11,651,727.34/3,921.51
6. Step 6: Final answer
   x = 2,971.23