Finding the Fourth Proportional to 2,620.69, 3,930.60 and 771.59

Step by Step Solution

1. Step 1: Write the proportion equation
   2,620.69 : 3,930.60 = 771.59 : x
2. Step 2: Convert to fraction form
   2,620.69/3,930.60 = 771.59/x
3. Step 3: Cross multiply
   2,620.69x = 3,930.60 × 771.59
4. Step 4: Simplify right side
   2,620.69x = 3,032,811.65
5. Step 5: Solve for x
   x = 3,032,811.65/2,620.69
6. Step 6: Final answer
   x = 1,157.26