Finding the Fourth Proportional to 2,168.20, 2,991.90 and 1,236.68

Step by Step Solution

1. Step 1: Write the proportion equation
   2,168.20 : 2,991.90 = 1,236.68 : x
2. Step 2: Convert to fraction form
   2,168.20/2,991.90 = 1,236.68/x
3. Step 3: Cross multiply
   2,168.20x = 2,991.90 × 1,236.68
4. Step 4: Simplify right side
   2,168.20x = 3,700,022.89
5. Step 5: Solve for x
   x = 3,700,022.89/2,168.20
6. Step 6: Final answer
   x = 1,706.50