Finding the Fourth Proportional to 2,139.88, 3,209.58 and 969.40

Step by Step Solution

1. Step 1: Write the proportion equation
   2,139.88 : 3,209.58 = 969.40 : x
2. Step 2: Convert to fraction form
   2,139.88/3,209.58 = 969.40/x
3. Step 3: Cross multiply
   2,139.88x = 3,209.58 × 969.40
4. Step 4: Simplify right side
   2,139.88x = 3,111,366.85
5. Step 5: Solve for x
   x = 3,111,366.85/2,139.88
6. Step 6: Final answer
   x = 1,453.99