Finding the Fourth Proportional to 2,139.84, 2,959.20 and 2,100.96

Step by Step Solution

1. Step 1: Write the proportion equation
   2,139.84 : 2,959.20 = 2,100.96 : x
2. Step 2: Convert to fraction form
   2,139.84/2,959.20 = 2,100.96/x
3. Step 3: Cross multiply
   2,139.84x = 2,959.20 × 2,100.96
4. Step 4: Simplify right side
   2,139.84x = 6,217,160.83
5. Step 5: Solve for x
   x = 6,217,160.83/2,139.84
6. Step 6: Final answer
   x = 2,905.43