Finding the Fourth Proportional to 2,651.92, 3,979 and 1,420.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,651.92 : 3,979 = 1,420.72 : x
2. Step 2: Convert to fraction form
   2,651.92/3,979 = 1,420.72/x
3. Step 3: Cross multiply
   2,651.92x = 3,979 × 1,420.72
4. Step 4: Simplify right side
   2,651.92x = 5,653,044.88
5. Step 5: Solve for x
   x = 5,653,044.88/2,651.92
6. Step 6: Final answer
   x = 2,131.68