Finding the Third Proportional to 307,724.50 and 639,911

Step by Step Solution

1. Step 1: Write the proportion equation
   307,724.50 : 639,911 = 639,911 : x
2. Step 2: Convert to fraction form
   307,724.50/639,911 = 639,911/x
3. Step 3: Cross multiply
   307,724.50x = 639,911 × 639,911
4. Step 4: Simplify right side
   307,724.50x = 409,486,087,921
5. Step 5: Solve for x
   x = 409,486,087,921/307,724.50
6. Step 6: Final answer
   x = 1,330,690.56