Finding the Fourth Proportional to 1,442.12, 2,165.34 and 1,391.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,442.12 : 2,165.34 = 1,391.72 : x
2. Step 2: Convert to fraction form
   1,442.12/2,165.34 = 1,391.72/x
3. Step 3: Cross multiply
   1,442.12x = 2,165.34 × 1,391.72
4. Step 4: Simplify right side
   1,442.12x = 3,013,546.98
5. Step 5: Solve for x
   x = 3,013,546.98/1,442.12
6. Step 6: Final answer
   x = 2,089.66