Finding the Fourth Proportional to 1,216.34, 1,678.52 and 685.22

Step by Step Solution

1. Step 1: Write the proportion equation
   1,216.34 : 1,678.52 = 685.22 : x
2. Step 2: Convert to fraction form
   1,216.34/1,678.52 = 685.22/x
3. Step 3: Cross multiply
   1,216.34x = 1,678.52 × 685.22
4. Step 4: Simplify right side
   1,216.34x = 1,150,143.66
5. Step 5: Solve for x
   x = 1,150,143.66/1,216.34
6. Step 6: Final answer
   x = 945.58