Finding the Fourth Proportional to 2,145.15, 3,218.06 and 912.56

Step by Step Solution

1. Step 1: Write the proportion equation
   2,145.15 : 3,218.06 = 912.56 : x
2. Step 2: Convert to fraction form
   2,145.15/3,218.06 = 912.56/x
3. Step 3: Cross multiply
   2,145.15x = 3,218.06 × 912.56
4. Step 4: Simplify right side
   2,145.15x = 2,936,672.83
5. Step 5: Solve for x
   x = 2,936,672.83/2,145.15
6. Step 6: Final answer
   x = 1,368.98