Finding the Third Proportional to 391,300.50 and 622,459.50

Step by Step Solution

1. Step 1: Write the proportion equation
   391,300.50 : 622,459.50 = 622,459.50 : x
2. Step 2: Convert to fraction form
   391,300.50/622,459.50 = 622,459.50/x
3. Step 3: Cross multiply
   391,300.50x = 622,459.50 × 622,459.50
4. Step 4: Simplify right side
   391,300.50x = 387,455,829,140.25
5. Step 5: Solve for x
   x = 387,455,829,140.25/391,300.50
6. Step 6: Final answer
   x = 990,174.63