Finding the Fourth Proportional to 2,809.59, 3,878.47 and 1,815.35

Step by Step Solution

1. Step 1: Write the proportion equation
   2,809.59 : 3,878.47 = 1,815.35 : x
2. Step 2: Convert to fraction form
   2,809.59/3,878.47 = 1,815.35/x
3. Step 3: Cross multiply
   2,809.59x = 3,878.47 × 1,815.35
4. Step 4: Simplify right side
   2,809.59x = 7,040,780.51
5. Step 5: Solve for x
   x = 7,040,780.51/2,809.59
6. Step 6: Final answer
   x = 2,505.98