Finding the Fourth Proportional to 3,891.86, 5,370.78 and 2,123.50

Step by Step Solution

1. Step 1: Write the proportion equation
   3,891.86 : 5,370.78 = 2,123.50 : x
2. Step 2: Convert to fraction form
   3,891.86/5,370.78 = 2,123.50/x
3. Step 3: Cross multiply
   3,891.86x = 5,370.78 × 2,123.50
4. Step 4: Simplify right side
   3,891.86x = 11,404,851.33
5. Step 5: Solve for x
   x = 11,404,851.33/3,891.86
6. Step 6: Final answer
   x = 2,930.44