Finding the Fourth Proportional to 2,105.93, 3,158.29 and 645.20

Step by Step Solution

1. Step 1: Write the proportion equation
   2,105.93 : 3,158.29 = 645.20 : x
2. Step 2: Convert to fraction form
   2,105.93/3,158.29 = 645.20/x
3. Step 3: Cross multiply
   2,105.93x = 3,158.29 × 645.20
4. Step 4: Simplify right side
   2,105.93x = 2,037,725.57
5. Step 5: Solve for x
   x = 2,037,725.57/2,105.93
6. Step 6: Final answer
   x = 967.61