Finding the Fourth Proportional to 1,210.29, 1,670.22 and 686.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,210.29 : 1,670.22 = 686.31 : x
2. Step 2: Convert to fraction form
   1,210.29/1,670.22 = 686.31/x
3. Step 3: Cross multiply
   1,210.29x = 1,670.22 × 686.31
4. Step 4: Simplify right side
   1,210.29x = 1,146,288.69
5. Step 5: Solve for x
   x = 1,146,288.69/1,210.29
6. Step 6: Final answer
   x = 947.12