Finding the Fourth Proportional to 31,407.20, 47,105.88 and 20,391.98

Step by Step Solution

1. Step 1: Write the proportion equation
   31,407.20 : 47,105.88 = 20,391.98 : x
2. Step 2: Convert to fraction form
   31,407.20/47,105.88 = 20,391.98/x
3. Step 3: Cross multiply
   31,407.20x = 47,105.88 × 20,391.98
4. Step 4: Simplify right side
   31,407.20x = 960,582,162.84
5. Step 5: Solve for x
   x = 960,582,162.84/31,407.20
6. Step 6: Final answer
   x = 30,584.78