Finding the Fourth Proportional to 1,636.61, 2,258.56 and 890.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,636.61 : 2,258.56 = 890.61 : x
2. Step 2: Convert to fraction form
   1,636.61/2,258.56 = 890.61/x
3. Step 3: Cross multiply
   1,636.61x = 2,258.56 × 890.61
4. Step 4: Simplify right side
   1,636.61x = 2,011,493.90
5. Step 5: Solve for x
   x = 2,011,493.90/1,636.61
6. Step 6: Final answer
   x = 1,229.06