Finding the Fourth Proportional to 30,524.41, 42,128.76 and 20,956.47

Step by Step Solution

1. Step 1: Write the proportion equation
   30,524.41 : 42,128.76 = 20,956.47 : x
2. Step 2: Convert to fraction form
   30,524.41/42,128.76 = 20,956.47/x
3. Step 3: Cross multiply
   30,524.41x = 42,128.76 × 20,956.47
4. Step 4: Simplify right side
   30,524.41x = 882,870,134.78
5. Step 5: Solve for x
   x = 882,870,134.78/30,524.41
6. Step 6: Final answer
   x = 28,923.42