Finding the Fourth Proportional to 30,686.48, 42,288.36 and 21,839.12

Step by Step Solution

1. Step 1: Write the proportion equation
   30,686.48 : 42,288.36 = 21,839.12 : x
2. Step 2: Convert to fraction form
   30,686.48/42,288.36 = 21,839.12/x
3. Step 3: Cross multiply
   30,686.48x = 42,288.36 × 21,839.12
4. Step 4: Simplify right side
   30,686.48x = 923,540,568.64
5. Step 5: Solve for x
   x = 923,540,568.64/30,686.48
6. Step 6: Final answer
   x = 30,096.01