Finding the Fourth Proportional to 1,142.96, 1,712.48 and 816.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,142.96 : 1,712.48 = 816.72 : x
2. Step 2: Convert to fraction form
   1,142.96/1,712.48 = 816.72/x
3. Step 3: Cross multiply
   1,142.96x = 1,712.48 × 816.72
4. Step 4: Simplify right side
   1,142.96x = 1,398,616.67
5. Step 5: Solve for x
   x = 1,398,616.67/1,142.96
6. Step 6: Final answer
   x = 1,223.68