Finding the Fourth Proportional to 1,172.18, 1,617.59 and 641.06

Step by Step Solution

1. Step 1: Write the proportion equation
   1,172.18 : 1,617.59 = 641.06 : x
2. Step 2: Convert to fraction form
   1,172.18/1,617.59 = 641.06/x
3. Step 3: Cross multiply
   1,172.18x = 1,617.59 × 641.06
4. Step 4: Simplify right side
   1,172.18x = 1,036,969.04
5. Step 5: Solve for x
   x = 1,036,969.04/1,172.18
6. Step 6: Final answer
   x = 884.65