Finding the Fourth Proportional to 1,116.38, 1,540.56 and 644.27

Step by Step Solution

1. Step 1: Write the proportion equation
   1,116.38 : 1,540.56 = 644.27 : x
2. Step 2: Convert to fraction form
   1,116.38/1,540.56 = 644.27/x
3. Step 3: Cross multiply
   1,116.38x = 1,540.56 × 644.27
4. Step 4: Simplify right side
   1,116.38x = 992,528.89
5. Step 5: Solve for x
   x = 992,528.89/1,116.38
6. Step 6: Final answer
   x = 889.06