Finding the Fourth Proportional to 1,081.81, 1,623.12 and 388.45

Step by Step Solution

1. Step 1: Write the proportion equation
   1,081.81 : 1,623.12 = 388.45 : x
2. Step 2: Convert to fraction form
   1,081.81/1,623.12 = 388.45/x
3. Step 3: Cross multiply
   1,081.81x = 1,623.12 × 388.45
4. Step 4: Simplify right side
   1,081.81x = 630,500.96
5. Step 5: Solve for x
   x = 630,500.96/1,081.81
6. Step 6: Final answer
   x = 582.82