Finding the Fourth Proportional to 1,072.71, 1,609.43 and 661.28

Step by Step Solution

1. Step 1: Write the proportion equation
   1,072.71 : 1,609.43 = 661.28 : x
2. Step 2: Convert to fraction form
   1,072.71/1,609.43 = 661.28/x
3. Step 3: Cross multiply
   1,072.71x = 1,609.43 × 661.28
4. Step 4: Simplify right side
   1,072.71x = 1,064,272.52
5. Step 5: Solve for x
   x = 1,064,272.52/1,072.71
6. Step 6: Final answer
   x = 992.13