Finding the Fourth Proportional to 2,109.57, 3,165.57 and 811.14

Step by Step Solution

1. Step 1: Write the proportion equation
   2,109.57 : 3,165.57 = 811.14 : x
2. Step 2: Convert to fraction form
   2,109.57/3,165.57 = 811.14/x
3. Step 3: Cross multiply
   2,109.57x = 3,165.57 × 811.14
4. Step 4: Simplify right side
   2,109.57x = 2,567,720.45
5. Step 5: Solve for x
   x = 2,567,720.45/2,109.57
6. Step 6: Final answer
   x = 1,217.18