Finding the Fourth Proportional to 2,170.78, 3,257.78 and 1,621.30

Step by Step Solution

1. Step 1: Write the proportion equation
   2,170.78 : 3,257.78 = 1,621.30 : x
2. Step 2: Convert to fraction form
   2,170.78/3,257.78 = 1,621.30/x
3. Step 3: Cross multiply
   2,170.78x = 3,257.78 × 1,621.30
4. Step 4: Simplify right side
   2,170.78x = 5,281,838.71
5. Step 5: Solve for x
   x = 5,281,838.71/2,170.78
6. Step 6: Final answer
   x = 2,433.15