Finding the Fourth Proportional to 1,018.32, 1,404.54 and 645.36

Step by Step Solution

1. Step 1: Write the proportion equation
   1,018.32 : 1,404.54 = 645.36 : x
2. Step 2: Convert to fraction form
   1,018.32/1,404.54 = 645.36/x
3. Step 3: Cross multiply
   1,018.32x = 1,404.54 × 645.36
4. Step 4: Simplify right side
   1,018.32x = 906,433.93
5. Step 5: Solve for x
   x = 906,433.93/1,018.32
6. Step 6: Final answer
   x = 890.13