Finding the Third Proportional to 12,858 and 19,956

Step by Step Solution

1. Step 1: Write the proportion equation
   12,858 : 19,956 = 19,956 : x
2. Step 2: Convert to fraction form
   12,858/19,956 = 19,956/x
3. Step 3: Cross multiply
   12,858x = 19,956 × 19,956
4. Step 4: Simplify right side
   12,858x = 398,241,936
5. Step 5: Solve for x
   x = 398,241,936/12,858
6. Step 6: Final answer
   x = 30,972.31