Finding the Fourth Proportional to 1,131.57, 1,562.49 and 921.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,131.57 : 1,562.49 = 921.78 : x
2. Step 2: Convert to fraction form
   1,131.57/1,562.49 = 921.78/x
3. Step 3: Cross multiply
   1,131.57x = 1,562.49 × 921.78
4. Step 4: Simplify right side
   1,131.57x = 1,440,272.03
5. Step 5: Solve for x
   x = 1,440,272.03/1,131.57
6. Step 6: Final answer
   x = 1,272.81