Finding the Fourth Proportional to 3,775.50, 5,657.78 and 2,128.55

Step by Step Solution

1. Step 1: Write the proportion equation
   3,775.50 : 5,657.78 = 2,128.55 : x
2. Step 2: Convert to fraction form
   3,775.50/5,657.78 = 2,128.55/x
3. Step 3: Cross multiply
   3,775.50x = 5,657.78 × 2,128.55
4. Step 4: Simplify right side
   3,775.50x = 12,042,828.69
5. Step 5: Solve for x
   x = 12,042,828.69/3,775.50
6. Step 6: Final answer
   x = 3,189.73