Finding the Fourth Proportional to 1,662.72, 2,489.28 and 1,278.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,662.72 : 2,489.28 = 1,278.72 : x
2. Step 2: Convert to fraction form
   1,662.72/2,489.28 = 1,278.72/x
3. Step 3: Cross multiply
   1,662.72x = 2,489.28 × 1,278.72
4. Step 4: Simplify right side
   1,662.72x = 3,183,092.12
5. Step 5: Solve for x
   x = 3,183,092.12/1,662.72
6. Step 6: Final answer
   x = 1,914.39