Finding the Fourth Proportional to 1,085.78, 1,628.69 and 355.41

Step by Step Solution

1. Step 1: Write the proportion equation
   1,085.78 : 1,628.69 = 355.41 : x
2. Step 2: Convert to fraction form
   1,085.78/1,628.69 = 355.41/x
3. Step 3: Cross multiply
   1,085.78x = 1,628.69 × 355.41
4. Step 4: Simplify right side
   1,085.78x = 578,850.94
5. Step 5: Solve for x
   x = 578,850.94/1,085.78
6. Step 6: Final answer
   x = 533.12