Finding the Fourth Proportional to 28,978.20, 39,990.42 and 16,231.27

Step by Step Solution

1. Step 1: Write the proportion equation
   28,978.20 : 39,990.42 = 16,231.27 : x
2. Step 2: Convert to fraction form
   28,978.20/39,990.42 = 16,231.27/x
3. Step 3: Cross multiply
   28,978.20x = 39,990.42 × 16,231.27
4. Step 4: Simplify right side
   28,978.20x = 649,095,118.64
5. Step 5: Solve for x
   x = 649,095,118.64/28,978.20
6. Step 6: Final answer
   x = 22,399.43