Finding the Fourth Proportional to 1,786.50, 2,678.61 and 689.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,786.50 : 2,678.61 = 689.55 : x
2. Step 2: Convert to fraction form
   1,786.50/2,678.61 = 689.55/x
3. Step 3: Cross multiply
   1,786.50x = 2,678.61 × 689.55
4. Step 4: Simplify right side
   1,786.50x = 1,847,035.53
5. Step 5: Solve for x
   x = 1,847,035.53/1,786.50
6. Step 6: Final answer
   x = 1,033.88