Finding the Fourth Proportional to 1,172.90, 1,618.61 and 648.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,172.90 : 1,618.61 = 648.96 : x
2. Step 2: Convert to fraction form
   1,172.90/1,618.61 = 648.96/x
3. Step 3: Cross multiply
   1,172.90x = 1,618.61 × 648.96
4. Step 4: Simplify right side
   1,172.90x = 1,050,413.15
5. Step 5: Solve for x
   x = 1,050,413.15/1,172.90
6. Step 6: Final answer
   x = 895.57