Finding the Fourth Proportional to 2,139.57, 3,209.35 and 985.33

Step by Step Solution

1. Step 1: Write the proportion equation
   2,139.57 : 3,209.35 = 985.33 : x
2. Step 2: Convert to fraction form
   2,139.57/3,209.35 = 985.33/x
3. Step 3: Cross multiply
   2,139.57x = 3,209.35 × 985.33
4. Step 4: Simplify right side
   2,139.57x = 3,162,268.84
5. Step 5: Solve for x
   x = 3,162,268.84/2,139.57
6. Step 6: Final answer
   x = 1,477.99