Finding the Third Proportional to 7,878 and 12,359

Step by Step Solution

1. Step 1: Write the proportion equation
   7,878 : 12,359 = 12,359 : x
2. Step 2: Convert to fraction form
   7,878/12,359 = 12,359/x
3. Step 3: Cross multiply
   7,878x = 12,359 × 12,359
4. Step 4: Simplify right side
   7,878x = 152,744,881
5. Step 5: Solve for x
   x = 152,744,881/7,878
6. Step 6: Final answer
   x = 19,388.79