Finding the Third Proportional to 351,816 and 686,134.50

Step by Step Solution

1. Step 1: Write the proportion equation
   351,816 : 686,134.50 = 686,134.50 : x
2. Step 2: Convert to fraction form
   351,816/686,134.50 = 686,134.50/x
3. Step 3: Cross multiply
   351,816x = 686,134.50 × 686,134.50
4. Step 4: Simplify right side
   351,816x = 470,780,552,090.25
5. Step 5: Solve for x
   x = 470,780,552,090.25/351,816
6. Step 6: Final answer
   x = 1,338,144.23