Finding the Fourth Proportional to 2,209.78, 3,316.04 and 911.25

Step by Step Solution

1. Step 1: Write the proportion equation
   2,209.78 : 3,316.04 = 911.25 : x
2. Step 2: Convert to fraction form
   2,209.78/3,316.04 = 911.25/x
3. Step 3: Cross multiply
   2,209.78x = 3,316.04 × 911.25
4. Step 4: Simplify right side
   2,209.78x = 3,021,740.31
5. Step 5: Solve for x
   x = 3,021,740.31/2,209.78
6. Step 6: Final answer
   x = 1,367.44