Finding the Fourth Proportional to 2,171.91, 3,249.74 and 1,291.20

Step by Step Solution

1. Step 1: Write the proportion equation
   2,171.91 : 3,249.74 = 1,291.20 : x
2. Step 2: Convert to fraction form
   2,171.91/3,249.74 = 1,291.20/x
3. Step 3: Cross multiply
   2,171.91x = 3,249.74 × 1,291.20
4. Step 4: Simplify right side
   2,171.91x = 4,196,057.83
5. Step 5: Solve for x
   x = 4,196,057.83/2,171.91
6. Step 6: Final answer
   x = 1,931.97