Finding the Fourth Proportional to 2,638.66, 3,956.66 and 1,405.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,638.66 : 3,956.66 = 1,405.72 : x
2. Step 2: Convert to fraction form
   2,638.66/3,956.66 = 1,405.72/x
3. Step 3: Cross multiply
   2,638.66x = 3,956.66 × 1,405.72
4. Step 4: Simplify right side
   2,638.66x = 5,561,956.10
5. Step 5: Solve for x
   x = 5,561,956.10/2,638.66
6. Step 6: Final answer
   x = 2,107.87