Finding the Fourth Proportional to 1,018.25, 1,404.63 and 645.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,018.25 : 1,404.63 = 645.09 : x
2. Step 2: Convert to fraction form
   1,018.25/1,404.63 = 645.09/x
3. Step 3: Cross multiply
   1,018.25x = 1,404.63 × 645.09
4. Step 4: Simplify right side
   1,018.25x = 906,112.77
5. Step 5: Solve for x
   x = 906,112.77/1,018.25
6. Step 6: Final answer
   x = 889.88