Finding the Fourth Proportional to 1,172.85, 1,618.50 and 648.87

Step by Step Solution

1. Step 1: Write the proportion equation
   1,172.85 : 1,618.50 = 648.87 : x
2. Step 2: Convert to fraction form
   1,172.85/1,618.50 = 648.87/x
3. Step 3: Cross multiply
   1,172.85x = 1,618.50 × 648.87
4. Step 4: Simplify right side
   1,172.85x = 1,050,196.10
5. Step 5: Solve for x
   x = 1,050,196.10/1,172.85
6. Step 6: Final answer
   x = 895.42