Finding the Fourth Proportional to 1,172.76, 1,618.30 and 648.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,172.76 : 1,618.30 = 648.78 : x
2. Step 2: Convert to fraction form
   1,172.76/1,618.30 = 648.78/x
3. Step 3: Cross multiply
   1,172.76x = 1,618.30 × 648.78
4. Step 4: Simplify right side
   1,172.76x = 1,049,920.67
5. Step 5: Solve for x
   x = 1,049,920.67/1,172.76
6. Step 6: Final answer
   x = 895.26