Finding the Fourth Proportional to 2,620.78, 3,910.18 and 2,091.22

Step by Step Solution

1. Step 1: Write the proportion equation
   2,620.78 : 3,910.18 = 2,091.22 : x
2. Step 2: Convert to fraction form
   2,620.78/3,910.18 = 2,091.22/x
3. Step 3: Cross multiply
   2,620.78x = 3,910.18 × 2,091.22
4. Step 4: Simplify right side
   2,620.78x = 8,177,036.16
5. Step 5: Solve for x
   x = 8,177,036.16/2,620.78
6. Step 6: Final answer
   x = 3,120.08