Finding the Third Proportional to 12,886.50 and 19,911.75

Step by Step Solution

1. Step 1: Write the proportion equation
   12,886.50 : 19,911.75 = 19,911.75 : x
2. Step 2: Convert to fraction form
   12,886.50/19,911.75 = 19,911.75/x
3. Step 3: Cross multiply
   12,886.50x = 19,911.75 × 19,911.75
4. Step 4: Simplify right side
   12,886.50x = 396,477,788.06
5. Step 5: Solve for x
   x = 396,477,788.06/12,886.50
6. Step 6: Final answer
   x = 30,766.91