Finding the Third Proportional to 351,819 and 686,140.50

Step by Step Solution

1. Step 1: Write the proportion equation
   351,819 : 686,140.50 = 686,140.50 : x
2. Step 2: Convert to fraction form
   351,819/686,140.50 = 686,140.50/x
3. Step 3: Cross multiply
   351,819x = 686,140.50 × 686,140.50
4. Step 4: Simplify right side
   351,819x = 470,788,785,740.25
5. Step 5: Solve for x
   x = 470,788,785,740.25/351,819
6. Step 6: Final answer
   x = 1,338,156.23