Finding the Fourth Proportional to 1,608.38, 2,219.61 and 900.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,608.38 : 2,219.61 = 900.20 : x
2. Step 2: Convert to fraction form
   1,608.38/2,219.61 = 900.20/x
3. Step 3: Cross multiply
   1,608.38x = 2,219.61 × 900.20
4. Step 4: Simplify right side
   1,608.38x = 1,998,088.42
5. Step 5: Solve for x
   x = 1,998,088.42/1,608.38
6. Step 6: Final answer
   x = 1,242.30