Finding the Fourth Proportional to 1,620.90, 2,431.33 and 1,099.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,620.90 : 2,431.33 = 1,099.61 : x
2. Step 2: Convert to fraction form
   1,620.90/2,431.33 = 1,099.61/x
3. Step 3: Cross multiply
   1,620.90x = 2,431.33 × 1,099.61
4. Step 4: Simplify right side
   1,620.90x = 2,673,499.88
5. Step 5: Solve for x
   x = 2,673,499.88/1,620.90
6. Step 6: Final answer
   x = 1,649.39