Finding the Fourth Proportional to 2,643.09, 3,956.89 and 1,390.73

Step by Step Solution

1. Step 1: Write the proportion equation
   2,643.09 : 3,956.89 = 1,390.73 : x
2. Step 2: Convert to fraction form
   2,643.09/3,956.89 = 1,390.73/x
3. Step 3: Cross multiply
   2,643.09x = 3,956.89 × 1,390.73
4. Step 4: Simplify right side
   2,643.09x = 5,502,970.84
5. Step 5: Solve for x
   x = 5,502,970.84/2,643.09
6. Step 6: Final answer
   x = 2,082.02