Finding the Fourth Proportional to 2,105.96, 3,159.06 and 644.98

Step by Step Solution

1. Step 1: Write the proportion equation
   2,105.96 : 3,159.06 = 644.98 : x
2. Step 2: Convert to fraction form
   2,105.96/3,159.06 = 644.98/x
3. Step 3: Cross multiply
   2,105.96x = 3,159.06 × 644.98
4. Step 4: Simplify right side
   2,105.96x = 2,037,530.52
5. Step 5: Solve for x
   x = 2,037,530.52/2,105.96
6. Step 6: Final answer
   x = 967.51