Finding the Fourth Proportional to 1,086.42, 1,499.22 and 644.06

Step by Step Solution

1. Step 1: Write the proportion equation
   1,086.42 : 1,499.22 = 644.06 : x
2. Step 2: Convert to fraction form
   1,086.42/1,499.22 = 644.06/x
3. Step 3: Cross multiply
   1,086.42x = 1,499.22 × 644.06
4. Step 4: Simplify right side
   1,086.42x = 965,576.92
5. Step 5: Solve for x
   x = 965,576.92/1,086.42
6. Step 6: Final answer
   x = 888.77