Finding the Third Proportional to 401,948 and 639,820.50

Step by Step Solution

1. Step 1: Write the proportion equation
   401,948 : 639,820.50 = 639,820.50 : x
2. Step 2: Convert to fraction form
   401,948/639,820.50 = 639,820.50/x
3. Step 3: Cross multiply
   401,948x = 639,820.50 × 639,820.50
4. Step 4: Simplify right side
   401,948x = 409,370,272,220.25
5. Step 5: Solve for x
   x = 409,370,272,220.25/401,948
6. Step 6: Final answer
   x = 1,018,465.75