Finding the Fourth Proportional to 1,636.61, 2,258.54 and 890.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,636.61 : 2,258.54 = 890.57 : x
2. Step 2: Convert to fraction form
   1,636.61/2,258.54 = 890.57/x
3. Step 3: Cross multiply
   1,636.61x = 2,258.54 × 890.57
4. Step 4: Simplify right side
   1,636.61x = 2,011,372.22
5. Step 5: Solve for x
   x = 2,011,372.22/1,636.61
6. Step 6: Final answer
   x = 1,228.99