Finding the Third Proportional to 11,686.78 and 15,662.11

Step by Step Solution

1. Step 1: Write the proportion equation
   11,686.78 : 15,662.11 = 15,662.11 : x
2. Step 2: Convert to fraction form
   11,686.78/15,662.11 = 15,662.11/x
3. Step 3: Cross multiply
   11,686.78x = 15,662.11 × 15,662.11
4. Step 4: Simplify right side
   11,686.78x = 245,301,670.07
5. Step 5: Solve for x
   x = 245,301,670.07/11,686.78
6. Step 6: Final answer
   x = 20,989.67