Finding the Fourth Proportional to 2,478.89, 3,421.35 and 1,639.64

Step by Step Solution

1. Step 1: Write the proportion equation
   2,478.89 : 3,421.35 = 1,639.64 : x
2. Step 2: Convert to fraction form
   2,478.89/3,421.35 = 1,639.64/x
3. Step 3: Cross multiply
   2,478.89x = 3,421.35 × 1,639.64
4. Step 4: Simplify right side
   2,478.89x = 5,609,782.31
5. Step 5: Solve for x
   x = 5,609,782.31/2,478.89
6. Step 6: Final answer
   x = 2,263.02