Finding the Fourth Proportional to 1,152.55, 1,728.15 and 787.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,152.55 : 1,728.15 = 787.78 : x
2. Step 2: Convert to fraction form
   1,152.55/1,728.15 = 787.78/x
3. Step 3: Cross multiply
   1,152.55x = 1,728.15 × 787.78
4. Step 4: Simplify right side
   1,152.55x = 1,361,402.01
5. Step 5: Solve for x
   x = 1,361,402.01/1,152.55
6. Step 6: Final answer
   x = 1,181.21