Finding the Fourth Proportional to 2,647.86, 3,968.66 and 1,086.90

Step by Step Solution

1. Step 1: Write the proportion equation
   2,647.86 : 3,968.66 = 1,086.90 : x
2. Step 2: Convert to fraction form
   2,647.86/3,968.66 = 1,086.90/x
3. Step 3: Cross multiply
   2,647.86x = 3,968.66 × 1,086.90
4. Step 4: Simplify right side
   2,647.86x = 4,313,536.55
5. Step 5: Solve for x
   x = 4,313,536.55/2,647.86
6. Step 6: Final answer
   x = 1,629.07