Finding the Fourth Proportional to 1,680.37, 2,318.57 and 981.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,680.37 : 2,318.57 = 981.61 : x
2. Step 2: Convert to fraction form
   1,680.37/2,318.57 = 981.61/x
3. Step 3: Cross multiply
   1,680.37x = 2,318.57 × 981.61
4. Step 4: Simplify right side
   1,680.37x = 2,275,923.25
5. Step 5: Solve for x
   x = 2,275,923.25/1,680.37
6. Step 6: Final answer
   x = 1,354.42