Finding the Fourth Proportional to 1,086.33, 1,499.14 and 644.28

Step by Step Solution

1. Step 1: Write the proportion equation
   1,086.33 : 1,499.14 = 644.28 : x
2. Step 2: Convert to fraction form
   1,086.33/1,499.14 = 644.28/x
3. Step 3: Cross multiply
   1,086.33x = 1,499.14 × 644.28
4. Step 4: Simplify right side
   1,086.33x = 965,865.92
5. Step 5: Solve for x
   x = 965,865.92/1,086.33
6. Step 6: Final answer
   x = 889.11