Finding the Fourth Proportional to 1,609.72, 2,221.27 and 911.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,609.72 : 2,221.27 = 911.10 : x
2. Step 2: Convert to fraction form
   1,609.72/2,221.27 = 911.10/x
3. Step 3: Cross multiply
   1,609.72x = 2,221.27 × 911.10
4. Step 4: Simplify right side
   1,609.72x = 2,023,795.75
5. Step 5: Solve for x
   x = 2,023,795.75/1,609.72
6. Step 6: Final answer
   x = 1,257.23