Finding the Fourth Proportional to 1,086.10, 1,628.55 and 355.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,086.10 : 1,628.55 = 355.30 : x
2. Step 2: Convert to fraction form
   1,086.10/1,628.55 = 355.30/x
3. Step 3: Cross multiply
   1,086.10x = 1,628.55 × 355.30
4. Step 4: Simplify right side
   1,086.10x = 578,623.82
5. Step 5: Solve for x
   x = 578,623.82/1,086.10
6. Step 6: Final answer
   x = 532.75