Finding the Fourth Proportional to 1,086.75, 1,499.52 and 644.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,086.75 : 1,499.52 = 644.55 : x
2. Step 2: Convert to fraction form
   1,086.75/1,499.52 = 644.55/x
3. Step 3: Cross multiply
   1,086.75x = 1,499.52 × 644.55
4. Step 4: Simplify right side
   1,086.75x = 966,515.62
5. Step 5: Solve for x
   x = 966,515.62/1,086.75
6. Step 6: Final answer
   x = 889.36