Finding the Fourth Proportional to 2,171.59, 2,996.93 and 1,287.20

Step by Step Solution

1. Step 1: Write the proportion equation
   2,171.59 : 2,996.93 = 1,287.20 : x
2. Step 2: Convert to fraction form
   2,171.59/2,996.93 = 1,287.20/x
3. Step 3: Cross multiply
   2,171.59x = 2,996.93 × 1,287.20
4. Step 4: Simplify right side
   2,171.59x = 3,857,648.30
5. Step 5: Solve for x
   x = 3,857,648.30/2,171.59
6. Step 6: Final answer
   x = 1,776.42