Finding the Fourth Proportional to 20,109.72, 30,120.84 and 13,506.60

Step by Step Solution

1. Step 1: Write the proportion equation
   20,109.72 : 30,120.84 = 13,506.60 : x
2. Step 2: Convert to fraction form
   20,109.72/30,120.84 = 13,506.60/x
3. Step 3: Cross multiply
   20,109.72x = 30,120.84 × 13,506.60
4. Step 4: Simplify right side
   20,109.72x = 406,830,137.54
5. Step 5: Solve for x
   x = 406,830,137.54/20,109.72
6. Step 6: Final answer
   x = 20,230.52