Finding the Fourth Proportional to 2,139, 2,949.90 and 1,392.27

Step by Step Solution

1. Step 1: Write the proportion equation
   2,139 : 2,949.90 = 1,392.27 : x
2. Step 2: Convert to fraction form
   2,139/2,949.90 = 1,392.27/x
3. Step 3: Cross multiply
   2,139x = 2,949.90 × 1,392.27
4. Step 4: Simplify right side
   2,139x = 4,107,057.27
5. Step 5: Solve for x
   x = 4,107,057.27/2,139
6. Step 6: Final answer
   x = 1,920.08