Finding the Fourth Proportional to 2,759.68, 4,139.10 and 811.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,759.68 : 4,139.10 = 811.72 : x
2. Step 2: Convert to fraction form
   2,759.68/4,139.10 = 811.72/x
3. Step 3: Cross multiply
   2,759.68x = 4,139.10 × 811.72
4. Step 4: Simplify right side
   2,759.68x = 3,359,790.25
5. Step 5: Solve for x
   x = 3,359,790.25/2,759.68
6. Step 6: Final answer
   x = 1,217.46