Finding the Fourth Proportional to 1,166.07, 1,609.16 and 642.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,166.07 : 1,609.16 = 642.09 : x
2. Step 2: Convert to fraction form
   1,166.07/1,609.16 = 642.09/x
3. Step 3: Cross multiply
   1,166.07x = 1,609.16 × 642.09
4. Step 4: Simplify right side
   1,166.07x = 1,033,222.33
5. Step 5: Solve for x
   x = 1,033,222.33/1,166.07
6. Step 6: Final answer
   x = 886.07