Finding the Fourth Proportional to 1,018.50, 1,404.97 and 645.34

Step by Step Solution

1. Step 1: Write the proportion equation
   1,018.50 : 1,404.97 = 645.34 : x
2. Step 2: Convert to fraction form
   1,018.50/1,404.97 = 645.34/x
3. Step 3: Cross multiply
   1,018.50x = 1,404.97 × 645.34
4. Step 4: Simplify right side
   1,018.50x = 906,683.34
5. Step 5: Solve for x
   x = 906,683.34/1,018.50
6. Step 6: Final answer
   x = 890.21