Finding the Fourth Proportional to 3,897.04, 5,377.86 and 2,128.72

Step by Step Solution

1. Step 1: Write the proportion equation
   3,897.04 : 5,377.86 = 2,128.72 : x
2. Step 2: Convert to fraction form
   3,897.04/5,377.86 = 2,128.72/x
3. Step 3: Cross multiply
   3,897.04x = 5,377.86 × 2,128.72
4. Step 4: Simplify right side
   3,897.04x = 11,447,958.14
5. Step 5: Solve for x
   x = 11,447,958.14/3,897.04
6. Step 6: Final answer
   x = 2,937.60