Finding the Third Proportional to 8,580 and 13,142

Step by Step Solution

1. Step 1: Write the proportion equation
   8,580 : 13,142 = 13,142 : x
2. Step 2: Convert to fraction form
   8,580/13,142 = 13,142/x
3. Step 3: Cross multiply
   8,580x = 13,142 × 13,142
4. Step 4: Simplify right side
   8,580x = 172,712,164
5. Step 5: Solve for x
   x = 172,712,164/8,580
6. Step 6: Final answer
   x = 20,129.62