Finding the Fourth Proportional to 2,154.15, 3,231.56 and 921.56

Step by Step Solution

1. Step 1: Write the proportion equation
   2,154.15 : 3,231.56 = 921.56 : x
2. Step 2: Convert to fraction form
   2,154.15/3,231.56 = 921.56/x
3. Step 3: Cross multiply
   2,154.15x = 3,231.56 × 921.56
4. Step 4: Simplify right side
   2,154.15x = 2,978,086.82
5. Step 5: Solve for x
   x = 2,978,086.82/2,154.15
6. Step 6: Final answer
   x = 1,382.49