Finding the Fourth Proportional to 3,926.45, 5,418.59 and 2,158.09

Step by Step Solution

1. Step 1: Write the proportion equation
   3,926.45 : 5,418.59 = 2,158.09 : x
2. Step 2: Convert to fraction form
   3,926.45/5,418.59 = 2,158.09/x
3. Step 3: Cross multiply
   3,926.45x = 5,418.59 × 2,158.09
4. Step 4: Simplify right side
   3,926.45x = 11,693,780.56
5. Step 5: Solve for x
   x = 11,693,780.56/3,926.45
6. Step 6: Final answer
   x = 2,978.21