Finding the Fourth Proportional to 1,018.20, 1,404.98 and 644.52

Step by Step Solution

1. Step 1: Write the proportion equation
   1,018.20 : 1,404.98 = 644.52 : x
2. Step 2: Convert to fraction form
   1,018.20/1,404.98 = 644.52/x
3. Step 3: Cross multiply
   1,018.20x = 1,404.98 × 644.52
4. Step 4: Simplify right side
   1,018.20x = 905,537.71
5. Step 5: Solve for x
   x = 905,537.71/1,018.20
6. Step 6: Final answer
   x = 889.35