Finding the Fourth Proportional to 20,071.60, 30,111.12 and 8,978.72

Step by Step Solution

1. Step 1: Write the proportion equation
   20,071.60 : 30,111.12 = 8,978.72 : x
2. Step 2: Convert to fraction form
   20,071.60/30,111.12 = 8,978.72/x
3. Step 3: Cross multiply
   20,071.60x = 30,111.12 × 8,978.72
4. Step 4: Simplify right side
   20,071.60x = 270,359,315.37
5. Step 5: Solve for x
   x = 270,359,315.37/20,071.60
6. Step 6: Final answer
   x = 13,469.74