Finding the Fourth Proportional to 1,018.26, 1,405.72 and 645.62

Step by Step Solution

1. Step 1: Write the proportion equation
   1,018.26 : 1,405.72 = 645.62 : x
2. Step 2: Convert to fraction form
   1,018.26/1,405.72 = 645.62/x
3. Step 3: Cross multiply
   1,018.26x = 1,405.72 × 645.62
4. Step 4: Simplify right side
   1,018.26x = 907,560.95
5. Step 5: Solve for x
   x = 907,560.95/1,018.26
6. Step 6: Final answer
   x = 891.29