Finding the Fourth Proportional to 2,638.79, 3,953.81 and 1,857.16

Step by Step Solution

1. Step 1: Write the proportion equation
   2,638.79 : 3,953.81 = 1,857.16 : x
2. Step 2: Convert to fraction form
   2,638.79/3,953.81 = 1,857.16/x
3. Step 3: Cross multiply
   2,638.79x = 3,953.81 × 1,857.16
4. Step 4: Simplify right side
   2,638.79x = 7,342,857.78
5. Step 5: Solve for x
   x = 7,342,857.78/2,638.79
6. Step 6: Final answer
   x = 2,782.66