Finding the Fourth Proportional to 1,018.42, 1,404.54 and 644.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,018.42 : 1,404.54 = 644.98 : x
2. Step 2: Convert to fraction form
   1,018.42/1,404.54 = 644.98/x
3. Step 3: Cross multiply
   1,018.42x = 1,404.54 × 644.98
4. Step 4: Simplify right side
   1,018.42x = 905,900.21
5. Step 5: Solve for x
   x = 905,900.21/1,018.42
6. Step 6: Final answer
   x = 889.52