Finding the Fourth Proportional to 1,116.33, 1,540.77 and 644.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,116.33 : 1,540.77 = 644.55 : x
2. Step 2: Convert to fraction form
   1,116.33/1,540.77 = 644.55/x
3. Step 3: Cross multiply
   1,116.33x = 1,540.77 × 644.55
4. Step 4: Simplify right side
   1,116.33x = 993,103.30
5. Step 5: Solve for x
   x = 993,103.30/1,116.33
6. Step 6: Final answer
   x = 889.61