Finding the Fourth Proportional to 1,219.89, 1,683.03 and 688.71

Step by Step Solution

1. Step 1: Write the proportion equation
   1,219.89 : 1,683.03 = 688.71 : x
2. Step 2: Convert to fraction form
   1,219.89/1,683.03 = 688.71/x
3. Step 3: Cross multiply
   1,219.89x = 1,683.03 × 688.71
4. Step 4: Simplify right side
   1,219.89x = 1,159,121.31
5. Step 5: Solve for x
   x = 1,159,121.31/1,219.89
6. Step 6: Final answer
   x = 950.19