Finding the Fourth Proportional to 1,217.33, 1,679.96 and 686.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,217.33 : 1,679.96 = 686.42 : x
2. Step 2: Convert to fraction form
   1,217.33/1,679.96 = 686.42/x
3. Step 3: Cross multiply
   1,217.33x = 1,679.96 × 686.42
4. Step 4: Simplify right side
   1,217.33x = 1,153,146.31
5. Step 5: Solve for x
   x = 1,153,146.31/1,217.33
6. Step 6: Final answer
   x = 947.28