Finding the Fourth Proportional to 1,072.88, 1,609.78 and 456.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,072.88 : 1,609.78 = 456.72 : x
2. Step 2: Convert to fraction form
   1,072.88/1,609.78 = 456.72/x
3. Step 3: Cross multiply
   1,072.88x = 1,609.78 × 456.72
4. Step 4: Simplify right side
   1,072.88x = 735,218.72
5. Step 5: Solve for x
   x = 735,218.72/1,072.88
6. Step 6: Final answer
   x = 685.28