Finding the Fourth Proportional to 1,165.89, 1,608.95 and 641.91

Step by Step Solution

1. Step 1: Write the proportion equation
   1,165.89 : 1,608.95 = 641.91 : x
2. Step 2: Convert to fraction form
   1,165.89/1,608.95 = 641.91/x
3. Step 3: Cross multiply
   1,165.89x = 1,608.95 × 641.91
4. Step 4: Simplify right side
   1,165.89x = 1,032,797.88
5. Step 5: Solve for x
   x = 1,032,797.88/1,165.89
6. Step 6: Final answer
   x = 885.85