Finding the Fourth Proportional to 1,172.89, 1,618.59 and 648.91

Step by Step Solution

1. Step 1: Write the proportion equation
   1,172.89 : 1,618.59 = 648.91 : x
2. Step 2: Convert to fraction form
   1,172.89/1,618.59 = 648.91/x
3. Step 3: Cross multiply
   1,172.89x = 1,618.59 × 648.91
4. Step 4: Simplify right side
   1,172.89x = 1,050,319.24
5. Step 5: Solve for x
   x = 1,050,319.24/1,172.89
6. Step 6: Final answer
   x = 895.50