Finding the Fourth Proportional to 2,439.21, 3,659.63 and 1,620.71

Step by Step Solution

1. Step 1: Write the proportion equation
   2,439.21 : 3,659.63 = 1,620.71 : x
2. Step 2: Convert to fraction form
   2,439.21/3,659.63 = 1,620.71/x
3. Step 3: Cross multiply
   2,439.21x = 3,659.63 × 1,620.71
4. Step 4: Simplify right side
   2,439.21x = 5,931,172.54
5. Step 5: Solve for x
   x = 5,931,172.54/2,439.21
6. Step 6: Final answer
   x = 2,431.60