Finding the Third Proportional to 312,822 and 686,553.75

Step by Step Solution

1. Step 1: Write the proportion equation
   312,822 : 686,553.75 = 686,553.75 : x
2. Step 2: Convert to fraction form
   312,822/686,553.75 = 686,553.75/x
3. Step 3: Cross multiply
   312,822x = 686,553.75 × 686,553.75
4. Step 4: Simplify right side
   312,822x = 471,356,051,639.06
5. Step 5: Solve for x
   x = 471,356,051,639.06/312,822
6. Step 6: Final answer
   x = 1,506,786.77