Finding the Fourth Proportional to 1,081.69, 1,622.73 and 642.74

Step by Step Solution

1. Step 1: Write the proportion equation
   1,081.69 : 1,622.73 = 642.74 : x
2. Step 2: Convert to fraction form
   1,081.69/1,622.73 = 642.74/x
3. Step 3: Cross multiply
   1,081.69x = 1,622.73 × 642.74
4. Step 4: Simplify right side
   1,081.69x = 1,042,987.78
5. Step 5: Solve for x
   x = 1,042,987.78/1,081.69
6. Step 6: Final answer
   x = 964.22