Finding the Fourth Proportional to 30,831.69, 42,518.85 and 20,465.10

Step by Step Solution

1. Step 1: Write the proportion equation
   30,831.69 : 42,518.85 = 20,465.10 : x
2. Step 2: Convert to fraction form
   30,831.69/42,518.85 = 20,465.10/x
3. Step 3: Cross multiply
   30,831.69x = 42,518.85 × 20,465.10
4. Step 4: Simplify right side
   30,831.69x = 870,152,517.14
5. Step 5: Solve for x
   x = 870,152,517.14/30,831.69
6. Step 6: Final answer
   x = 28,222.67