Finding the Fourth Proportional to 2,621.40, 3,931.31 and 772.47

Step by Step Solution

1. Step 1: Write the proportion equation
   2,621.40 : 3,931.31 = 772.47 : x
2. Step 2: Convert to fraction form
   2,621.40/3,931.31 = 772.47/x
3. Step 3: Cross multiply
   2,621.40x = 3,931.31 × 772.47
4. Step 4: Simplify right side
   2,621.40x = 3,036,820.97
5. Step 5: Solve for x
   x = 3,036,820.97/2,621.40
6. Step 6: Final answer
   x = 1,158.47