Finding the Fourth Proportional to 2,212.04, 3,315.90 and 912.80

Step by Step Solution

1. Step 1: Write the proportion equation
   2,212.04 : 3,315.90 = 912.80 : x
2. Step 2: Convert to fraction form
   2,212.04/3,315.90 = 912.80/x
3. Step 3: Cross multiply
   2,212.04x = 3,315.90 × 912.80
4. Step 4: Simplify right side
   2,212.04x = 3,026,753.52
5. Step 5: Solve for x
   x = 3,026,753.52/2,212.04
6. Step 6: Final answer
   x = 1,368.31