Finding the Fourth Proportional to 1,086.70, 1,498.94 and 644.27

Step by Step Solution

1. Step 1: Write the proportion equation
   1,086.70 : 1,498.94 = 644.27 : x
2. Step 2: Convert to fraction form
   1,086.70/1,498.94 = 644.27/x
3. Step 3: Cross multiply
   1,086.70x = 1,498.94 × 644.27
4. Step 4: Simplify right side
   1,086.70x = 965,718.85
5. Step 5: Solve for x
   x = 965,718.85/1,086.70
6. Step 6: Final answer
   x = 888.68