Finding the Fourth Proportional to 2,620.34, 3,931.07 and 771.30

Step by Step Solution

1. Step 1: Write the proportion equation
   2,620.34 : 3,931.07 = 771.30 : x
2. Step 2: Convert to fraction form
   2,620.34/3,931.07 = 771.30/x
3. Step 3: Cross multiply
   2,620.34x = 3,931.07 × 771.30
4. Step 4: Simplify right side
   2,620.34x = 3,032,034.29
5. Step 5: Solve for x
   x = 3,032,034.29/2,620.34
6. Step 6: Final answer
   x = 1,157.11