Finding the Third Proportional to 3,400 and 7,870

Step by Step Solution

1. Step 1: Write the proportion equation
   3,400 : 7,870 = 7,870 : x
2. Step 2: Convert to fraction form
   3,400/7,870 = 7,870/x
3. Step 3: Cross multiply
   3,400x = 7,870 × 7,870
4. Step 4: Simplify right side
   3,400x = 61,936,900
5. Step 5: Solve for x
   x = 61,936,900/3,400
6. Step 6: Final answer
   x = 18,216.74