Finding the Fourth Proportional to 2,209.91, 3,315.15 and 911.07

Step by Step Solution

1. Step 1: Write the proportion equation
   2,209.91 : 3,315.15 = 911.07 : x
2. Step 2: Convert to fraction form
   2,209.91/3,315.15 = 911.07/x
3. Step 3: Cross multiply
   2,209.91x = 3,315.15 × 911.07
4. Step 4: Simplify right side
   2,209.91x = 3,020,333.71
5. Step 5: Solve for x
   x = 3,020,333.71/2,209.91
6. Step 6: Final answer
   x = 1,366.73