Finding the Fourth Proportional to 2,171.55, 3,259.15 and 939.90

Step by Step Solution

1. Step 1: Write the proportion equation
   2,171.55 : 3,259.15 = 939.90 : x
2. Step 2: Convert to fraction form
   2,171.55/3,259.15 = 939.90/x
3. Step 3: Cross multiply
   2,171.55x = 3,259.15 × 939.90
4. Step 4: Simplify right side
   2,171.55x = 3,063,270.39
5. Step 5: Solve for x
   x = 3,063,270.39/2,171.55
6. Step 6: Final answer
   x = 1,410.64