Finding the Fourth Proportional to 2,231.72, 3,079.94 and 1,392.45

Step by Step Solution

1. Step 1: Write the proportion equation
   2,231.72 : 3,079.94 = 1,392.45 : x
2. Step 2: Convert to fraction form
   2,231.72/3,079.94 = 1,392.45/x
3. Step 3: Cross multiply
   2,231.72x = 3,079.94 × 1,392.45
4. Step 4: Simplify right side
   2,231.72x = 4,288,662.45
5. Step 5: Solve for x
   x = 4,288,662.45/2,231.72
6. Step 6: Final answer
   x = 1,921.68