Finding the Fourth Proportional to 796.91, 1,187.56 and 770.78

Step by Step Solution

1. Step 1: Write the proportion equation
   796.91 : 1,187.56 = 770.78 : x
2. Step 2: Convert to fraction form
   796.91/1,187.56 = 770.78/x
3. Step 3: Cross multiply
   796.91x = 1,187.56 × 770.78
4. Step 4: Simplify right side
   796.91x = 915,351.43
5. Step 5: Solve for x
   x = 915,351.43/796.91
6. Step 6: Final answer
   x = 1,148.63