Finding the Fourth Proportional to 1,081.54, 1,621.34 and 388.05

Step by Step Solution

1. Step 1: Write the proportion equation
   1,081.54 : 1,621.34 = 388.05 : x
2. Step 2: Convert to fraction form
   1,081.54/1,621.34 = 388.05/x
3. Step 3: Cross multiply
   1,081.54x = 1,621.34 × 388.05
4. Step 4: Simplify right side
   1,081.54x = 629,160.07
5. Step 5: Solve for x
   x = 629,160.07/1,081.54
6. Step 6: Final answer
   x = 581.72