Finding the Fourth Proportional to 1,680.30, 2,318.67 and 981.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,680.30 : 2,318.67 = 981.72 : x
2. Step 2: Convert to fraction form
   1,680.30/2,318.67 = 981.72/x
3. Step 3: Cross multiply
   1,680.30x = 2,318.67 × 981.72
4. Step 4: Simplify right side
   1,680.30x = 2,276,284.71
5. Step 5: Solve for x
   x = 2,276,284.71/1,680.30
6. Step 6: Final answer
   x = 1,354.69