Finding the Fourth Proportional to 2,166.96, 2,990.39 and 1,172.23

Step by Step Solution

1. Step 1: Write the proportion equation
   2,166.96 : 2,990.39 = 1,172.23 : x
2. Step 2: Convert to fraction form
   2,166.96/2,990.39 = 1,172.23/x
3. Step 3: Cross multiply
   2,166.96x = 2,990.39 × 1,172.23
4. Step 4: Simplify right side
   2,166.96x = 3,505,429.42
5. Step 5: Solve for x
   x = 3,505,429.42/2,166.96
6. Step 6: Final answer
   x = 1,617.68