Finding the Third Proportional to 142,399.50 and 311,399

Step by Step Solution

1. Step 1: Write the proportion equation
   142,399.50 : 311,399 = 311,399 : x
2. Step 2: Convert to fraction form
   142,399.50/311,399 = 311,399/x
3. Step 3: Cross multiply
   142,399.50x = 311,399 × 311,399
4. Step 4: Simplify right side
   142,399.50x = 96,969,337,201
5. Step 5: Solve for x
   x = 96,969,337,201/142,399.50
6. Step 6: Final answer
   x = 680,966.84