Finding the Third Proportional to 1,620 and 3,870

Step by Step Solution

1. Step 1: Write the proportion equation
   1,620 : 3,870 = 3,870 : x
2. Step 2: Convert to fraction form
   1,620/3,870 = 3,870/x
3. Step 3: Cross multiply
   1,620x = 3,870 × 3,870
4. Step 4: Simplify right side
   1,620x = 14,976,900
5. Step 5: Solve for x
   x = 14,976,900/1,620
6. Step 6: Final answer
   x = 9,245