Finding the Fourth Proportional to 2,171.76, 2,997.72 and 1,387.92

Step by Step Solution

1. Step 1: Write the proportion equation
   2,171.76 : 2,997.72 = 1,387.92 : x
2. Step 2: Convert to fraction form
   2,171.76/2,997.72 = 1,387.92/x
3. Step 3: Cross multiply
   2,171.76x = 2,997.72 × 1,387.92
4. Step 4: Simplify right side
   2,171.76x = 4,160,595.54
5. Step 5: Solve for x
   x = 4,160,595.54/2,171.76
6. Step 6: Final answer
   x = 1,915.77