Finding the Fourth Proportional to 2,105.10, 3,157.86 and 644.04

Step by Step Solution

1. Step 1: Write the proportion equation
   2,105.10 : 3,157.86 = 644.04 : x
2. Step 2: Convert to fraction form
   2,105.10/3,157.86 = 644.04/x
3. Step 3: Cross multiply
   2,105.10x = 3,157.86 × 644.04
4. Step 4: Simplify right side
   2,105.10x = 2,033,788.15
5. Step 5: Solve for x
   x = 2,033,788.15/2,105.10
6. Step 6: Final answer
   x = 966.12