Finding the Fourth Proportional to 1,636.72, 2,258.62 and 890.65

Step by Step Solution

1. Step 1: Write the proportion equation
   1,636.72 : 2,258.62 = 890.65 : x
2. Step 2: Convert to fraction form
   1,636.72/2,258.62 = 890.65/x
3. Step 3: Cross multiply
   1,636.72x = 2,258.62 × 890.65
4. Step 4: Simplify right side
   1,636.72x = 2,011,635.45
5. Step 5: Solve for x
   x = 2,011,635.45/1,636.72
6. Step 6: Final answer
   x = 1,229.07