Finding the Fourth Proportional to 1,217.59, 1,680.24 and 686.46

Step by Step Solution

1. Step 1: Write the proportion equation
   1,217.59 : 1,680.24 = 686.46 : x
2. Step 2: Convert to fraction form
   1,217.59/1,680.24 = 686.46/x
3. Step 3: Cross multiply
   1,217.59x = 1,680.24 × 686.46
4. Step 4: Simplify right side
   1,217.59x = 1,153,417.55
5. Step 5: Solve for x
   x = 1,153,417.55/1,217.59
6. Step 6: Final answer
   x = 947.30