Finding the Fourth Proportional to 2,651.97, 3,978.77 and 921.81

Step by Step Solution

1. Step 1: Write the proportion equation
   2,651.97 : 3,978.77 = 921.81 : x
2. Step 2: Convert to fraction form
   2,651.97/3,978.77 = 921.81/x
3. Step 3: Cross multiply
   2,651.97x = 3,978.77 × 921.81
4. Step 4: Simplify right side
   2,651.97x = 3,667,665.36
5. Step 5: Solve for x
   x = 3,667,665.36/2,651.97
6. Step 6: Final answer
   x = 1,383.00