Finding the Fourth Proportional to 2,105.72, 3,158.98 and 645.02

Step by Step Solution

1. Step 1: Write the proportion equation
   2,105.72 : 3,158.98 = 645.02 : x
2. Step 2: Convert to fraction form
   2,105.72/3,158.98 = 645.02/x
3. Step 3: Cross multiply
   2,105.72x = 3,158.98 × 645.02
4. Step 4: Simplify right side
   2,105.72x = 2,037,605.28
5. Step 5: Solve for x
   x = 2,037,605.28/2,105.72
6. Step 6: Final answer
   x = 967.65