Finding the Fourth Proportional to 2,274.72, 3,139.20 and 1,390.92

Step by Step Solution

1. Step 1: Write the proportion equation
   2,274.72 : 3,139.20 = 1,390.92 : x
2. Step 2: Convert to fraction form
   2,274.72/3,139.20 = 1,390.92/x
3. Step 3: Cross multiply
   2,274.72x = 3,139.20 × 1,390.92
4. Step 4: Simplify right side
   2,274.72x = 4,366,376.06
5. Step 5: Solve for x
   x = 4,366,376.06/2,274.72
6. Step 6: Final answer
   x = 1,919.52