Finding the Fourth Proportional to 1,086.51, 1,499.41 and 644.46

Step by Step Solution

1. Step 1: Write the proportion equation
   1,086.51 : 1,499.41 = 644.46 : x
2. Step 2: Convert to fraction form
   1,086.51/1,499.41 = 644.46/x
3. Step 3: Cross multiply
   1,086.51x = 1,499.41 × 644.46
4. Step 4: Simplify right side
   1,086.51x = 966,304.95
5. Step 5: Solve for x
   x = 966,304.95/1,086.51
6. Step 6: Final answer
   x = 889.36