Finding the Fourth Proportional to 1,018.44, 1,404.50 and 644.79

Step by Step Solution

1. Step 1: Write the proportion equation
   1,018.44 : 1,404.50 = 644.79 : x
2. Step 2: Convert to fraction form
   1,018.44/1,404.50 = 644.79/x
3. Step 3: Cross multiply
   1,018.44x = 1,404.50 × 644.79
4. Step 4: Simplify right side
   1,018.44x = 905,597.31
5. Step 5: Solve for x
   x = 905,597.31/1,018.44
6. Step 6: Final answer
   x = 889.20