Finding the Third Proportional to 89,172 and 138,519

Step by Step Solution

1. Step 1: Write the proportion equation
   89,172 : 138,519 = 138,519 : x
2. Step 2: Convert to fraction form
   89,172/138,519 = 138,519/x
3. Step 3: Cross multiply
   89,172x = 138,519 × 138,519
4. Step 4: Simplify right side
   89,172x = 19,187,513,361
5. Step 5: Solve for x
   x = 19,187,513,361/89,172
6. Step 6: Final answer
   x = 215,174.20