Finding the Fourth Proportional to 1,918.35, 2,647.57 and 1,172.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,918.35 : 2,647.57 = 1,172.15 : x
2. Step 2: Convert to fraction form
   1,918.35/2,647.57 = 1,172.15/x
3. Step 3: Cross multiply
   1,918.35x = 2,647.57 × 1,172.15
4. Step 4: Simplify right side
   1,918.35x = 3,103,352.86
5. Step 5: Solve for x
   x = 3,103,352.86/1,918.35
6. Step 6: Final answer
   x = 1,617.72