Finding the Fourth Proportional to 2,564.12, 3,846.57 and 921.05

Step by Step Solution

1. Step 1: Write the proportion equation
   2,564.12 : 3,846.57 = 921.05 : x
2. Step 2: Convert to fraction form
   2,564.12/3,846.57 = 921.05/x
3. Step 3: Cross multiply
   2,564.12x = 3,846.57 × 921.05
4. Step 4: Simplify right side
   2,564.12x = 3,542,901.85
5. Step 5: Solve for x
   x = 3,542,901.85/2,564.12
6. Step 6: Final answer
   x = 1,381.72