Finding the Fourth Proportional to 1,080.62, 1,621.86 and 431.82

Step by Step Solution

1. Step 1: Write the proportion equation
   1,080.62 : 1,621.86 = 431.82 : x
2. Step 2: Convert to fraction form
   1,080.62/1,621.86 = 431.82/x
3. Step 3: Cross multiply
   1,080.62x = 1,621.86 × 431.82
4. Step 4: Simplify right side
   1,080.62x = 700,351.59
5. Step 5: Solve for x
   x = 700,351.59/1,080.62
6. Step 6: Final answer
   x = 648.10