Finding the Fourth Proportional to 1,107.89, 1,658.61 and 644.25

Step by Step Solution

1. Step 1: Write the proportion equation
   1,107.89 : 1,658.61 = 644.25 : x
2. Step 2: Convert to fraction form
   1,107.89/1,658.61 = 644.25/x
3. Step 3: Cross multiply
   1,107.89x = 1,658.61 × 644.25
4. Step 4: Simplify right side
   1,107.89x = 1,068,556.27
5. Step 5: Solve for x
   x = 1,068,556.27/1,107.89
6. Step 6: Final answer
   x = 964.50