Finding the Fourth Proportional to 2,620.38, 3,930.12 and 771.48

Step by Step Solution

1. Step 1: Write the proportion equation
   2,620.38 : 3,930.12 = 771.48 : x
2. Step 2: Convert to fraction form
   2,620.38/3,930.12 = 771.48/x
3. Step 3: Cross multiply
   2,620.38x = 3,930.12 × 771.48
4. Step 4: Simplify right side
   2,620.38x = 3,032,008.98
5. Step 5: Solve for x
   x = 3,032,008.98/2,620.38
6. Step 6: Final answer
   x = 1,157.09