Finding the Fourth Proportional to 1,215.78, 1,678.46 and 796.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,215.78 : 1,678.46 = 796.56 : x
2. Step 2: Convert to fraction form
   1,215.78/1,678.46 = 796.56/x
3. Step 3: Cross multiply
   1,215.78x = 1,678.46 × 796.56
4. Step 4: Simplify right side
   1,215.78x = 1,336,994.10
5. Step 5: Solve for x
   x = 1,336,994.10/1,215.78
6. Step 6: Final answer
   x = 1,099.70