Finding the Fourth Proportional to 2,153.76, 3,231.68 and 921.52

Step by Step Solution

1. Step 1: Write the proportion equation
   2,153.76 : 3,231.68 = 921.52 : x
2. Step 2: Convert to fraction form
   2,153.76/3,231.68 = 921.52/x
3. Step 3: Cross multiply
   2,153.76x = 3,231.68 × 921.52
4. Step 4: Simplify right side
   2,153.76x = 2,978,057.75
5. Step 5: Solve for x
   x = 2,978,057.75/2,153.76
6. Step 6: Final answer
   x = 1,382.72