Finding the Fourth Proportional to 1,640.20, 2,259.50 and 1,219.83

Step by Step Solution

1. Step 1: Write the proportion equation
   1,640.20 : 2,259.50 = 1,219.83 : x
2. Step 2: Convert to fraction form
   1,640.20/2,259.50 = 1,219.83/x
3. Step 3: Cross multiply
   1,640.20x = 2,259.50 × 1,219.83
4. Step 4: Simplify right side
   1,640.20x = 2,756,205.89
5. Step 5: Solve for x
   x = 2,756,205.89/1,640.20
6. Step 6: Final answer
   x = 1,680.41