Finding the Fourth Proportional to 2,629.42, 3,944.34 and 780.40

Step by Step Solution

1. Step 1: Write the proportion equation
   2,629.42 : 3,944.34 = 780.40 : x
2. Step 2: Convert to fraction form
   2,629.42/3,944.34 = 780.40/x
3. Step 3: Cross multiply
   2,629.42x = 3,944.34 × 780.40
4. Step 4: Simplify right side
   2,629.42x = 3,078,162.94
5. Step 5: Solve for x
   x = 3,078,162.94/2,629.42
6. Step 6: Final answer
   x = 1,170.66