Finding the Fourth Proportional to 1,099.50, 1,648.91 and 638.18

Step by Step Solution

1. Step 1: Write the proportion equation
   1,099.50 : 1,648.91 = 638.18 : x
2. Step 2: Convert to fraction form
   1,099.50/1,648.91 = 638.18/x
3. Step 3: Cross multiply
   1,099.50x = 1,648.91 × 638.18
4. Step 4: Simplify right side
   1,099.50x = 1,052,297.33
5. Step 5: Solve for x
   x = 1,052,297.33/1,099.50
6. Step 6: Final answer
   x = 957.07