Finding the Fourth Proportional to 1,210.27, 1,670.17 and 686.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,210.27 : 1,670.17 = 686.30 : x
2. Step 2: Convert to fraction form
   1,210.27/1,670.17 = 686.30/x
3. Step 3: Cross multiply
   1,210.27x = 1,670.17 × 686.30
4. Step 4: Simplify right side
   1,210.27x = 1,146,233.87
5. Step 5: Solve for x
   x = 1,146,233.87/1,210.27
6. Step 6: Final answer
   x = 947.09