Finding the Fourth Proportional to 2,105.58, 3,158.88 and 644.75

Step by Step Solution

1. Step 1: Write the proportion equation
   2,105.58 : 3,158.88 = 644.75 : x
2. Step 2: Convert to fraction form
   2,105.58/3,158.88 = 644.75/x
3. Step 3: Cross multiply
   2,105.58x = 3,158.88 × 644.75
4. Step 4: Simplify right side
   2,105.58x = 2,036,687.88
5. Step 5: Solve for x
   x = 2,036,687.88/2,105.58
6. Step 6: Final answer
   x = 967.28