Finding the Fourth Proportional to 1,172.67, 1,618.27 and 641.54

Step by Step Solution

1. Step 1: Write the proportion equation
   1,172.67 : 1,618.27 = 641.54 : x
2. Step 2: Convert to fraction form
   1,172.67/1,618.27 = 641.54/x
3. Step 3: Cross multiply
   1,172.67x = 1,618.27 × 641.54
4. Step 4: Simplify right side
   1,172.67x = 1,038,183.33
5. Step 5: Solve for x
   x = 1,038,183.33/1,172.67
6. Step 6: Final answer
   x = 885.32