Finding the Fourth Proportional to 2,078.81, 3,118.82 and 780.38

Step by Step Solution

1. Step 1: Write the proportion equation
   2,078.81 : 3,118.82 = 780.38 : x
2. Step 2: Convert to fraction form
   2,078.81/3,118.82 = 780.38/x
3. Step 3: Cross multiply
   2,078.81x = 3,118.82 × 780.38
4. Step 4: Simplify right side
   2,078.81x = 2,433,845.26
5. Step 5: Solve for x
   x = 2,433,845.26/2,078.81
6. Step 6: Final answer
   x = 1,170.79