Finding the Fourth Proportional to 2,172.61, 3,258.31 and 1,678.71

Step by Step Solution

1. Step 1: Write the proportion equation
   2,172.61 : 3,258.31 = 1,678.71 : x
2. Step 2: Convert to fraction form
   2,172.61/3,258.31 = 1,678.71/x
3. Step 3: Cross multiply
   2,172.61x = 3,258.31 × 1,678.71
4. Step 4: Simplify right side
   2,172.61x = 5,469,757.58
5. Step 5: Solve for x
   x = 5,469,757.58/2,172.61
6. Step 6: Final answer
   x = 2,517.60