Finding the Fourth Proportional to 3,111.24, 4,292.28 and 2,166.78

Step by Step Solution

1. Step 1: Write the proportion equation
   3,111.24 : 4,292.28 = 2,166.78 : x
2. Step 2: Convert to fraction form
   3,111.24/4,292.28 = 2,166.78/x
3. Step 3: Cross multiply
   3,111.24x = 4,292.28 × 2,166.78
4. Step 4: Simplify right side
   3,111.24x = 9,300,426.46
5. Step 5: Solve for x
   x = 9,300,426.46/3,111.24
6. Step 6: Final answer
   x = 2,989.30