Finding the Fourth Proportional to 31,456.28, 47,230.89 and 20,991.48

Step by Step Solution

1. Step 1: Write the proportion equation
   31,456.28 : 47,230.89 = 20,991.48 : x
2. Step 2: Convert to fraction form
   31,456.28/47,230.89 = 20,991.48/x
3. Step 3: Cross multiply
   31,456.28x = 47,230.89 × 20,991.48
4. Step 4: Simplify right side
   31,456.28x = 991,446,282.82
5. Step 5: Solve for x
   x = 991,446,282.82/31,456.28
6. Step 6: Final answer
   x = 31,518.23