Finding the Third Proportional to 401,961.50 and 639,842

Step by Step Solution

1. Step 1: Write the proportion equation
   401,961.50 : 639,842 = 639,842 : x
2. Step 2: Convert to fraction form
   401,961.50/639,842 = 639,842/x
3. Step 3: Cross multiply
   401,961.50x = 639,842 × 639,842
4. Step 4: Simplify right side
   401,961.50x = 409,397,784,964
5. Step 5: Solve for x
   x = 409,397,784,964/401,961.50
6. Step 6: Final answer
   x = 1,018,499.99