Finding the Fourth Proportional to 1,086.24, 1,498.80 and 644.29

Step by Step Solution

1. Step 1: Write the proportion equation
   1,086.24 : 1,498.80 = 644.29 : x
2. Step 2: Convert to fraction form
   1,086.24/1,498.80 = 644.29/x
3. Step 3: Cross multiply
   1,086.24x = 1,498.80 × 644.29
4. Step 4: Simplify right side
   1,086.24x = 965,660.52
5. Step 5: Solve for x
   x = 965,660.52/1,086.24
6. Step 6: Final answer
   x = 888.99