Finding the Fourth Proportional to 2,105.56, 3,158.36 and 644.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,105.56 : 3,158.36 = 644.72 : x
2. Step 2: Convert to fraction form
   2,105.56/3,158.36 = 644.72/x
3. Step 3: Cross multiply
   2,105.56x = 3,158.36 × 644.72
4. Step 4: Simplify right side
   2,105.56x = 2,036,257.86
5. Step 5: Solve for x
   x = 2,036,257.86/2,105.56
6. Step 6: Final answer
   x = 967.09