Finding the Fourth Proportional to 2,645.81, 3,969.14 and 1,085.75

Step by Step Solution

1. Step 1: Write the proportion equation
   2,645.81 : 3,969.14 = 1,085.75 : x
2. Step 2: Convert to fraction form
   2,645.81/3,969.14 = 1,085.75/x
3. Step 3: Cross multiply
   2,645.81x = 3,969.14 × 1,085.75
4. Step 4: Simplify right side
   2,645.81x = 4,309,468.48
5. Step 5: Solve for x
   x = 4,309,468.48/2,645.81
6. Step 6: Final answer
   x = 1,628.79