Finding the Fourth Proportional to 2,112.39, 3,168.18 and 813.69

Step by Step Solution

1. Step 1: Write the proportion equation
   2,112.39 : 3,168.18 = 813.69 : x
2. Step 2: Convert to fraction form
   2,112.39/3,168.18 = 813.69/x
3. Step 3: Cross multiply
   2,112.39x = 3,168.18 × 813.69
4. Step 4: Simplify right side
   2,112.39x = 2,577,916.38
5. Step 5: Solve for x
   x = 2,577,916.38/2,112.39
6. Step 6: Final answer
   x = 1,220.38