Finding the Fourth Proportional to 1,086.38, 1,499.22 and 644.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,086.38 : 1,499.22 = 644.12 : x
2. Step 2: Convert to fraction form
   1,086.38/1,499.22 = 644.12/x
3. Step 3: Cross multiply
   1,086.38x = 1,499.22 × 644.12
4. Step 4: Simplify right side
   1,086.38x = 965,670.09
5. Step 5: Solve for x
   x = 965,670.09/1,086.38
6. Step 6: Final answer
   x = 888.89