Finding the Third Proportional to 213,558 and 309,321

Step by Step Solution

1. Step 1: Write the proportion equation
   213,558 : 309,321 = 309,321 : x
2. Step 2: Convert to fraction form
   213,558/309,321 = 309,321/x
3. Step 3: Cross multiply
   213,558x = 309,321 × 309,321
4. Step 4: Simplify right side
   213,558x = 95,679,481,041
5. Step 5: Solve for x
   x = 95,679,481,041/213,558
6. Step 6: Final answer
   x = 448,025.74