Finding the Fourth Proportional to 2,759.81, 4,139.69 and 811.98

Step by Step Solution

1. Step 1: Write the proportion equation
   2,759.81 : 4,139.69 = 811.98 : x
2. Step 2: Convert to fraction form
   2,759.81/4,139.69 = 811.98/x
3. Step 3: Cross multiply
   2,759.81x = 4,139.69 × 811.98
4. Step 4: Simplify right side
   2,759.81x = 3,361,341.43
5. Step 5: Solve for x
   x = 3,361,341.43/2,759.81
6. Step 6: Final answer
   x = 1,217.96