Finding the Fourth Proportional to 1,141.78, 1,711.42 and 816.16

Step by Step Solution

1. Step 1: Write the proportion equation
   1,141.78 : 1,711.42 = 816.16 : x
2. Step 2: Convert to fraction form
   1,141.78/1,711.42 = 816.16/x
3. Step 3: Cross multiply
   1,141.78x = 1,711.42 × 816.16
4. Step 4: Simplify right side
   1,141.78x = 1,396,792.55
5. Step 5: Solve for x
   x = 1,396,792.55/1,141.78
6. Step 6: Final answer
   x = 1,223.35