Finding the Third Proportional to 12,678 and 19,678.50

Step by Step Solution

1. Step 1: Write the proportion equation
   12,678 : 19,678.50 = 19,678.50 : x
2. Step 2: Convert to fraction form
   12,678/19,678.50 = 19,678.50/x
3. Step 3: Cross multiply
   12,678x = 19,678.50 × 19,678.50
4. Step 4: Simplify right side
   12,678x = 387,243,362.25
5. Step 5: Solve for x
   x = 387,243,362.25/12,678
6. Step 6: Final answer
   x = 30,544.52