Finding the Fourth Proportional to 12,815.08, 17,685.71 and 7,150.21

Step by Step Solution

1. Step 1: Write the proportion equation
   12,815.08 : 17,685.71 = 7,150.21 : x
2. Step 2: Convert to fraction form
   12,815.08/17,685.71 = 7,150.21/x
3. Step 3: Cross multiply
   12,815.08x = 17,685.71 × 7,150.21
4. Step 4: Simplify right side
   12,815.08x = 126,456,487.35
5. Step 5: Solve for x
   x = 126,456,487.35/12,815.08
6. Step 6: Final answer
   x = 9,867.79