Finding the Fourth Proportional to 2,105.76, 3,158.46 and 644.97

Step by Step Solution

1. Step 1: Write the proportion equation
   2,105.76 : 3,158.46 = 644.97 : x
2. Step 2: Convert to fraction form
   2,105.76/3,158.46 = 644.97/x
3. Step 3: Cross multiply
   2,105.76x = 3,158.46 × 644.97
4. Step 4: Simplify right side
   2,105.76x = 2,037,111.95
5. Step 5: Solve for x
   x = 2,037,111.95/2,105.76
6. Step 6: Final answer
   x = 967.40