Finding the Fourth Proportional to 1,210.25, 1,670.35 and 686.59

Step by Step Solution

1. Step 1: Write the proportion equation
   1,210.25 : 1,670.35 = 686.59 : x
2. Step 2: Convert to fraction form
   1,210.25/1,670.35 = 686.59/x
3. Step 3: Cross multiply
   1,210.25x = 1,670.35 × 686.59
4. Step 4: Simplify right side
   1,210.25x = 1,146,845.61
5. Step 5: Solve for x
   x = 1,146,845.61/1,210.25
6. Step 6: Final answer
   x = 947.61