Finding the Fourth Proportional to 1,216.37, 1,678.53 and 685.34

Step by Step Solution

1. Step 1: Write the proportion equation
   1,216.37 : 1,678.53 = 685.34 : x
2. Step 2: Convert to fraction form
   1,216.37/1,678.53 = 685.34/x
3. Step 3: Cross multiply
   1,216.37x = 1,678.53 × 685.34
4. Step 4: Simplify right side
   1,216.37x = 1,150,363.75
5. Step 5: Solve for x
   x = 1,150,363.75/1,216.37
6. Step 6: Final answer
   x = 945.74