Finding the Third Proportional to 18,679.50 and 39,870

Step by Step Solution

1. Step 1: Write the proportion equation
   18,679.50 : 39,870 = 39,870 : x
2. Step 2: Convert to fraction form
   18,679.50/39,870 = 39,870/x
3. Step 3: Cross multiply
   18,679.50x = 39,870 × 39,870
4. Step 4: Simplify right side
   18,679.50x = 1,589,616,900
5. Step 5: Solve for x
   x = 1,589,616,900/18,679.50
6. Step 6: Final answer
   x = 85,099.54