Finding the Fourth Proportional to 1,245.72, 1,719.10 and 686.17

Step by Step Solution

1. Step 1: Write the proportion equation
   1,245.72 : 1,719.10 = 686.17 : x
2. Step 2: Convert to fraction form
   1,245.72/1,719.10 = 686.17/x
3. Step 3: Cross multiply
   1,245.72x = 1,719.10 × 686.17
4. Step 4: Simplify right side
   1,245.72x = 1,179,594.85
5. Step 5: Solve for x
   x = 1,179,594.85/1,245.72
6. Step 6: Final answer
   x = 946.92