Finding the Third Proportional to 643,986 and 1,398,618

Step by Step Solution

1. Step 1: Write the proportion equation
   643,986 : 1,398,618 = 1,398,618 : x
2. Step 2: Convert to fraction form
   643,986/1,398,618 = 1,398,618/x
3. Step 3: Cross multiply
   643,986x = 1,398,618 × 1,398,618
4. Step 4: Simplify right side
   643,986x = 1,956,132,309,924
5. Step 5: Solve for x
   x = 1,956,132,309,924/643,986
6. Step 6: Final answer
   x = 3,037,538.56