Finding the Fourth Proportional to 30,631.12, 42,287 and 20,612.24

Step by Step Solution

1. Step 1: Write the proportion equation
   30,631.12 : 42,287 = 20,612.24 : x
2. Step 2: Convert to fraction form
   30,631.12/42,287 = 20,612.24/x
3. Step 3: Cross multiply
   30,631.12x = 42,287 × 20,612.24
4. Step 4: Simplify right side
   30,631.12x = 871,629,792.88
5. Step 5: Solve for x
   x = 871,629,792.88/30,631.12
6. Step 6: Final answer
   x = 28,455.69