Finding the Fourth Proportional to 2,109.81, 3,166.17 and 811.29

Step by Step Solution

1. Step 1: Write the proportion equation
   2,109.81 : 3,166.17 = 811.29 : x
2. Step 2: Convert to fraction form
   2,109.81/3,166.17 = 811.29/x
3. Step 3: Cross multiply
   2,109.81x = 3,166.17 × 811.29
4. Step 4: Simplify right side
   2,109.81x = 2,568,682.06
5. Step 5: Solve for x
   x = 2,568,682.06/2,109.81
6. Step 6: Final answer
   x = 1,217.49