Finding the Third Proportional to 12,661.31 and 18,921.09

Step by Step Solution

1. Step 1: Write the proportion equation
   12,661.31 : 18,921.09 = 18,921.09 : x
2. Step 2: Convert to fraction form
   12,661.31/18,921.09 = 18,921.09/x
3. Step 3: Cross multiply
   12,661.31x = 18,921.09 × 18,921.09
4. Step 4: Simplify right side
   12,661.31x = 358,007,788.70
5. Step 5: Solve for x
   x = 358,007,788.70/12,661.31
6. Step 6: Final answer
   x = 28,275.72