Finding the Third Proportional to 643,820 and 1,385,816

Step by Step Solution

1. Step 1: Write the proportion equation
   643,820 : 1,385,816 = 1,385,816 : x
2. Step 2: Convert to fraction form
   643,820/1,385,816 = 1,385,816/x
3. Step 3: Cross multiply
   643,820x = 1,385,816 × 1,385,816
4. Step 4: Simplify right side
   643,820x = 1,920,485,985,856
5. Step 5: Solve for x
   x = 1,920,485,985,856/643,820
6. Step 6: Final answer
   x = 2,982,954.84