Finding the Fourth Proportional to 20,128.64, 30,179.18 and 10,248.80

Step by Step Solution

1. Step 1: Write the proportion equation
   20,128.64 : 30,179.18 = 10,248.80 : x
2. Step 2: Convert to fraction form
   20,128.64/30,179.18 = 10,248.80/x
3. Step 3: Cross multiply
   20,128.64x = 30,179.18 × 10,248.80
4. Step 4: Simplify right side
   20,128.64x = 309,300,379.98
5. Step 5: Solve for x
   x = 309,300,379.98/20,128.64
6. Step 6: Final answer
   x = 15,366.18