Finding the Fourth Proportional to 30,513.78, 42,128.58 and 20,950.58

Step by Step Solution

1. Step 1: Write the proportion equation
   30,513.78 : 42,128.58 = 20,950.58 : x
2. Step 2: Convert to fraction form
   30,513.78/42,128.58 = 20,950.58/x
3. Step 3: Cross multiply
   30,513.78x = 42,128.58 × 20,950.58
4. Step 4: Simplify right side
   30,513.78x = 882,617,974.93
5. Step 5: Solve for x
   x = 882,617,974.93/30,513.78
6. Step 6: Final answer
   x = 28,925.23