Finding the Third Proportional to 212,842.50 and 318,678

Step by Step Solution

1. Step 1: Write the proportion equation
   212,842.50 : 318,678 = 318,678 : x
2. Step 2: Convert to fraction form
   212,842.50/318,678 = 318,678/x
3. Step 3: Cross multiply
   212,842.50x = 318,678 × 318,678
4. Step 4: Simplify right side
   212,842.50x = 101,555,667,684
5. Step 5: Solve for x
   x = 101,555,667,684/212,842.50
6. Step 6: Final answer
   x = 477,139.99