Finding the Fourth Proportional to 1,219.34, 1,682.61 and 688.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,219.34 : 1,682.61 = 688.31 : x
2. Step 2: Convert to fraction form
   1,219.34/1,682.61 = 688.31/x
3. Step 3: Cross multiply
   1,219.34x = 1,682.61 × 688.31
4. Step 4: Simplify right side
   1,219.34x = 1,158,148.88
5. Step 5: Solve for x
   x = 1,158,148.88/1,219.34
6. Step 6: Final answer
   x = 949.82