Finding the Fourth Proportional to 2,116.39, 2,920.57 and 1,172.15

Step by Step Solution

1. Step 1: Write the proportion equation
   2,116.39 : 2,920.57 = 1,172.15 : x
2. Step 2: Convert to fraction form
   2,116.39/2,920.57 = 1,172.15/x
3. Step 3: Cross multiply
   2,116.39x = 2,920.57 × 1,172.15
4. Step 4: Simplify right side
   2,116.39x = 3,423,362.57
5. Step 5: Solve for x
   x = 3,423,362.57/2,116.39
6. Step 6: Final answer
   x = 1,617.55