Finding the Fourth Proportional to 2,112.34, 3,165.09 and 1,288.12

Step by Step Solution

1. Step 1: Write the proportion equation
   2,112.34 : 3,165.09 = 1,288.12 : x
2. Step 2: Convert to fraction form
   2,112.34/3,165.09 = 1,288.12/x
3. Step 3: Cross multiply
   2,112.34x = 3,165.09 × 1,288.12
4. Step 4: Simplify right side
   2,112.34x = 4,077,015.73
5. Step 5: Solve for x
   x = 4,077,015.73/2,112.34
6. Step 6: Final answer
   x = 1,930.09