Finding the Third Proportional to 8,513 and 13,215

Step by Step Solution

1. Step 1: Write the proportion equation
   8,513 : 13,215 = 13,215 : x
2. Step 2: Convert to fraction form
   8,513/13,215 = 13,215/x
3. Step 3: Cross multiply
   8,513x = 13,215 × 13,215
4. Step 4: Simplify right side
   8,513x = 174,636,225
5. Step 5: Solve for x
   x = 174,636,225/8,513
6. Step 6: Final answer
   x = 20,514.06