Finding the Fourth Proportional to 15,111.74, 20,855.61 and 9,144.88

Step by Step Solution

1. Step 1: Write the proportion equation
   15,111.74 : 20,855.61 = 9,144.88 : x
2. Step 2: Convert to fraction form
   15,111.74/20,855.61 = 9,144.88/x
3. Step 3: Cross multiply
   15,111.74x = 20,855.61 × 9,144.88
4. Step 4: Simplify right side
   15,111.74x = 190,722,050.78
5. Step 5: Solve for x
   x = 190,722,050.78/15,111.74
6. Step 6: Final answer
   x = 12,620.79