Finding the Fourth Proportional to 2,638.89, 3,958.38 and 2,478.51

Step by Step Solution

1. Step 1: Write the proportion equation
   2,638.89 : 3,958.38 = 2,478.51 : x
2. Step 2: Convert to fraction form
   2,638.89/3,958.38 = 2,478.51/x
3. Step 3: Cross multiply
   2,638.89x = 3,958.38 × 2,478.51
4. Step 4: Simplify right side
   2,638.89x = 9,810,884.41
5. Step 5: Solve for x
   x = 9,810,884.41/2,638.89
6. Step 6: Final answer
   x = 3,717.81