Finding the Fourth Proportional to 1,609.94, 2,221.71 and 911.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,609.94 : 2,221.71 = 911.31 : x
2. Step 2: Convert to fraction form
   1,609.94/2,221.71 = 911.31/x
3. Step 3: Cross multiply
   1,609.94x = 2,221.71 × 911.31
4. Step 4: Simplify right side
   1,609.94x = 2,024,675.51
5. Step 5: Solve for x
   x = 2,024,675.51/1,609.94
6. Step 6: Final answer
   x = 1,257.61